WorldWideScience

Sample records for erythrocytes oxygen sensors

  1. Erythrocyte signal transduction pathways, their oxygenation dependence and functional significance.

    Science.gov (United States)

    Barvitenko, Nadezhda N; Adragna, Norma C; Weber, Roy E

    2005-01-01

    Erythrocytes play a key role in human and vertebrate metabolism. Tissue O2 supply is regulated by both hemoglobin (Hb)-O2 affinity and erythrocyte rheology, a key determinant of tissue perfusion. Oxygenation-deoxygenation transitions of Hb may lead to re-organization of the cytoskeleton and signalling pathways activation/deactivation in an O2-dependent manner. Deoxygenated Hb binds to the cytoplasmic domain of the anion exchanger band 3, which is anchored to the cytoskeleton, and is considered a major mechanism underlying the oxygenation-dependence of several erythrocyte functions. This work discusses the multiple modes of Hb-cytoskeleton interactions. In addition, it reviews the effects of Mg2+, 2,3-diphosphoglycerate, NO, shear stress and Ca2+, all factors accompanying the oxygenation-deoxygenation cycle in circulating red cells. Due to the extensive literature on the subject, the data discussed here, pertain mainly to human erythrocytes whose O2 affinity is modulated by 2,3-diphosphoglycerate, ectothermic vertebrate erythrocytes that use ATP, and to bird erythrocytes that use inositol pentaphosphate. Copyright 2005 S. Karger AG, Basel.

  2. Novel nanostructured oxygen sensor

    Science.gov (United States)

    Boardman, Alan James

    New government regulations and industry requirements for medical oxygen sensors require the development of alternate materials and process optimization of primary sensor components. Current oxygen sensors are not compliant with the Restriction of Hazardous Substances (RoHS) Directive. This work focused on two areas. First, was finding suitable readily available materials for the sensor anodes. Second was optimizing the processing of the sensor cathode membrane for reduced delamination. Oxygen sensors were made using tin (Sn) and bismuth (Bi) electrodes, potassium hydroxide (KOH) and acetic acid (CH3COOH) electrolytes with platinum (Pt) and gold (Au) reference electrodes. Bi electrodes were fabricated by casting and pressing processes. Electrochemical characterization of the Sn and Bi electrodes was performed by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and sensing characterization per BSEN ISO 21647:2009 at various oxygen percentages, 0%, 20.9% and 100% oxygen levels with an automated test apparatus. The Sn anode with both electrolyte solutions showed good oxygen sensing properties and performance in a sensor. This system shows promise for replacement of Pb electrodes as required by the RoHS Directive. The Bi anode with Au cathode in both KOH and CH3COOH electrolytes showed acceptable performance and oxygen sensing properties. The Bi anodes fabricated by separate manufacturing methods demonstrated effectiveness for use in medical oxygen sensors. Gold thin films were prepared by magnetron sputtering on Flouroethylene Polymer (FEP) films. The FEP substrate temperature ranged from -77°C to 50°C. X-Ray Diffraction (XRD) and 4-point resistivity characterized the effects of substrate temperature to Au thin film particle size. XRD peak broadening and resistivity measurements showed a strong correlation of particle size to FEP substrate temperature. Particle size at 50°C was 594A and the -77°C particle size was 2.4 x 103A. Substrate

  3. Effects of whole-body gamma irradiation on oxygen transport by rat erythrocytes

    International Nuclear Information System (INIS)

    Thiriot, Christian; Kergonou, J.F.; Rocquet, Guy; Allary, Michel; Saint-Blancard, Jacques

    1982-01-01

    In this work, we studied the influence of whole-body gamma irradiation (8 Gy) upon oxygen transport by erythrocytes, through the erythrocyte count and related parameters, and through the factors affecting the oxygen affinity of hemoglobin. The oxygen affinity of hemoglobin is increased from day D + 5 after irradiation, and a severe erythropenia develops from day D + 8. These modifications probably result in tissue hypoxia via diminished oxygen transport from lungs to tissues, and decreased oxygen release from oxyhemoglobin in tissues

  4. Exhaustive Exercise-induced Oxidative Stress Alteration of Erythrocyte Oxygen Release Capacity.

    Science.gov (United States)

    Xiong, Yanlian; Xiong, Yanlei; Wang, Yueming; Zhao, Yajin; Li, Yaojin; Ren, Yang; Wang, Ruofeng; Zhao, Mingzi; Hao, Yitong; Liu, Haibei; Wang, Xiang

    2018-05-24

    The aim of the present study is to explore the effect of exhaustive running exercise (ERE) in the oxygen release capacity of rat erythrocytes. Rats were divided into sedentary control (C), moderate running exercise (MRE) and exhaustive running exercise groups. The thermodynamics and kinetics properties of the erythrocyte oxygen release process of different groups were tested. We also determined the degree of band-3 oxidative and phosphorylation, anion transport activity and carbonic anhydrase isoform II(CAII) activity. Biochemical studies suggested that exhaustive running significantly increased oxidative injury parameters in TBARS and methaemoglobin levels. Furthermore, exhaustive running significantly decreased anion transport activity and carbonic anhydrase isoform II(CAII) activity. Thermodynamic analysis indicated that erythrocytes oxygen release ability also significantly increased due to elevated 2,3-DPG level after exhaustive running. Kinetic analysis indicated that exhaustive running resulted in significantly decreased T50 value. We presented evidence that exhaustive running remarkably impacted thermodynamics and kinetics properties of RBCs oxygen release. In addition, changes in 2,3-DPG levels and band-3 oxidation and phosphorylation could be the driving force for exhaustive running induced alterations in erythrocytes oxygen release thermodynamics and kinetics properties.

  5. Effects of whole body UV-irradiation on oxygen delivery from the erythrocyte

    International Nuclear Information System (INIS)

    Humpeler, E.; Mairbaeurl, H.; Hoenigsmann, H.

    1982-01-01

    In 16 healthy caucasian volunteers (mean age: 22.2 years) the influence of whole body UV-irradiation on the oxygen transport properties of erythrocytes was investigated. Four hours after irradiation with UV (using the minimal erythema dose, MED) no variation of haemoglobin concentration, hematocrit, mean corpuscular haemoglobin concentration, pH or standard bicarbonate could be found, whereas inorganic plasma phosphate (Psub(i)), calcium, the intraerythrocytic 2,3-diphosphoglycerate (2,3-DPG), the activity of erythrocytic phosphofructokinase (PFK) and pyruvatekinase (PK) increased significantly. The half saturation tension of oxygen (P 50 -value) tended to increase. The increase of Psub(i) causes - via a stimulation of the glycolytic pathway - an increase in 2,3-DPG concentration and thus results in a shift of the oxygen dissociation curve. It is therefore possible to enhance tissue oxygenation by whole body UV-irradiation. (orig.)

  6. Robust high temperature oxygen sensor electrodes

    DEFF Research Database (Denmark)

    Lund, Anders

    Platinum is the most widely used material in high temperature oxygen sensor electrodes. However, platinum is expensive and the platinum electrode may, under certain conditions, suffer from poisoning, which is detrimental for an oxygen sensor. The objective of this thesis is to evaluate electrode...... materials as candidates for robust oxygen sensor electrodes. The present work focuses on characterising the electrochemical properties of a few electrode materials to understand which oxygen electrode processes are limiting for the response time of the sensor electrode. Three types of porous platinum......-Dansensor. The electrochemical properties of the electrodes were characterised by electrochemical impedance spectroscopy (EIS), and the structures were characterised by x-ray diffraction and electron microscopy. At an oxygen partial pressures of 0.2 bar, the response time of the sensor electrode was determined by oxygen...

  7. Limitations of potentiometric oxygen sensors operating at low oxygen levels

    DEFF Research Database (Denmark)

    Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels

    2011-01-01

    The electrochemical processes that limit the range of oxygen partial pressures in which potentiometric oxygen sensors can be used, were analysed using a theoretical and an experimental approach. Electrochemical impedance spectroscopy was performed on porous Pt/yttria stabilised zirconia (YSZ......) electrodes between 10−6 and 0.2 bar and at temperatures between 500 and 950 °C. The flow of oxide ions and electron holes through a sensor cell, with a YSZ electrolyte, were calculated under similar conditions. The oxygen permeation of the sensor cell was insignificant at an oxygen partial pressure of 10......−6 bar for an inlet flow rate higher than 2 L h−1 between 600 and 800 °C. The polarisation resistance measured between 10−6 and 10−4 bar was found to be inversely proportional to the oxygen partial pressure, nearly temperature independent and inversely proportional to the inlet gas flow rate, which shows...

  8. [Impact of oxygen toxic action on the erythrocyte membrane and possibility of estimating central nervous system function disturbances].

    Science.gov (United States)

    Belić, Branislava; Cincović, Marko R

    2011-07-01

    BACKGROUND/AIM; Prolonged exposure to hyperbaric oxygen leads to changes of erythrocytes shape as a consequence of toxic effects of oxygen on the erythrocyte membrane. The aim of this study was to examine the association between occurance of pathological forms of erythrocytes at different time from the start of hyperbaric oxygenation and the moment of convulsions occurrence, an interrelationship of different pathological forms of erythrocytes during exposure to hyperbaric oxygenation, as well as the correlation between the presence of ruptured erythrocytes and function of central nervous system (CNS) after completion of hyperbaric treatment. Sixty laboratory mice, Mus musculus, were exposed to the wholly-oxygen pressure of 3.5 absolute atmospheres (ATA). Blood was collected at the 32nd, 34th, 36th, 38th and 40th minutes after the exposure to oxygen. Pathological forms of erythrocytes were examined by electron microscopy. A moment of convulsions occurrence was registered in all animals. After decompression neurological examinations of experimental animals were perfomed. The Pearson's coefficient of correlation, and linear regression equations for the parameters outlined in the aim of the study were calculated. Hyperbaric oxygen caused damages of erythrocytes at the 34th minute after beginning of the treatment. Various forms of abnormal red blood cells occured, and immediately before the occurrence of irreversible changes (erythrocyte membrane rupture) echinocyte shape was dominated. A significant correlation between the number of damaged red blood cells at 34th minute and their number at the 36th, 38th and 40th minute was found. Convulsions were diagnosed significantly earlier in mice with a greater number of damaged red blood cells (p potential burden of CNS after cessation of hyperbaric oxygenation.

  9. [Role of erythrocyte cytoplasmic structures in changes in the affinity of haemoglobin for oxygen].

    Science.gov (United States)

    Bryzgalova, N Iu; Brazhe, N A; Iusipovich, A U; Maksimov, G V; Rubin, A B

    2009-01-01

    Changes in the refractive index of the cytoplasm and the affinity of haemoporphyrin of erythrocyte haemoglobin to oxygen (pH, 2,3-diphosphoglycerate) have been investigated using laser interference microscopy and Raman spectroscopy. It has been established that a decrease in pH and an increase in the content of 2,3-diphosphoglycerate are accompanied by changes in both the form of the cell and the refractive index of the cytoplasm and the affinity of haemoporphyrin of hemoglobin to oxygen. It has been shown that as pH is reduced, the capacity of haemoporphyrin for binding oxygen decreases and as the concentration of 2,3-diphosphoglycerate is increased, the ability of haemoporphyrin for oxygen reabsorption increases.

  10. Resistive Oxygen Gas Sensors for Harsh Environments

    Science.gov (United States)

    Moos, Ralf; Izu, Noriya; Rettig, Frank; Reiß, Sebastian; Shin, Woosuck; Matsubara, Ichiro

    2011-01-01

    Resistive oxygen sensors are an inexpensive alternative to the classical potentiometric zirconia oxygen sensor, especially for use in harsh environments and at temperatures of several hundred °C or even higher. This device-oriented paper gives a historical overview on the development of these sensor materials. It focuses especially on approaches to obtain a temperature independent behavior. It is shown that although in the past 40 years there have always been several research groups working concurrently with resistive oxygen sensors, novel ideas continue to emerge today with respect to improvements of the sensor response time, the temperature dependence, the long-term stability or the manufacture of the devices themselves using novel techniques for the sensitive films. Materials that are the focus of this review are metal oxides; especially titania, titanates, and ceria-based formulations. PMID:22163805

  11. Impact of oxygen toxic action on the erythrocyte membrane and possibility of estimating central nervous system function disturbances

    Directory of Open Access Journals (Sweden)

    Belić Branislava

    2011-01-01

    Full Text Available Background/Aim. Prolonged exposure to hyperbaric oxygen leads to changes of erythrocytes shape as a consequence of toxic effects of oxygen on the erythrocyte membrane. The aim of this study was to examine the association between occurance of pathological forms of erythrocytes at different time from the start of hyperbaric oxygenation and the moment of convulsions occurrence, an interrelationship of different pathological forms of erythrocytes during exposure to hyperbaric oxygenation, as well as the correlation between the presence of ruptured erythrocytes and function of central nervous system (CNS after completion of hyperbaric treatment. Methods. Sixty laboratory mice, Mus musculus, were exposed to the wholly-oxygen pressure of 3.5 absolute atmospheres (ATA. Blood was collected at the 32nd, 34th, 36th, 38th and 40th minutes after the exposure to oxygen. Pathological forms of erythrocytes were examined by electron microscopy. A moment of convulsions occurrence was registered in all animals. After decompression neurological examinations of experimental animals were perfomed. The Pearson's coefficient of correlation, and linear regression equations for the parameters outlined in the aim of the study were calculated. Results. Hyperbaric oxygen caused damages of erythrocytes at the 34th minute after beginning of the treatment. Various forms of abnormal red blood cells occured, and immediately before the occurrence of irreversible changes (erythrocyte membrane rupture echinocyte shape was dominated. A significant correlation between the number of damaged red blood cells at 34th minute and their number at the 36th, 38th and 40th minute was found. Convulsions were diagnosed significantly earlier in mice with a greater number of damaged red blood cells (p < 0.01. There was a negative correlation between the number of irreversiblly damaged red blood cells (ruptured at the 40th minute and neurological score in the studied animals (p < 0.05. Conclusion

  12. Numerical analysis of the effects of a high gradient magnetic field on flowing erythrocytes in a membrane oxygenator

    International Nuclear Information System (INIS)

    Mitamura, Yoshinori; Okamoto, Eiji

    2015-01-01

    This study was carried out to clarify the effect of a high gradient magnetic field on pressure characteristics of blood in a hollow fiber membrane oxygenator in a solenoid coil by means of numerical analysis. Deoxygenated erythrocytes are paramagnetic, and oxygenated erythrocytes are diamagnetic. Blood changes its magnetic susceptibility depending on whether it is carrying oxygen or not. Motion of blood was analyzed by solving the continuous equation and the Navier–Stokes equation. It was confirmed that oxygenation of deoxygenated blood in the downstream side of the applied magnetic field was effective for pressure rise in a non-uniform magnetic field. The pressure rise was enhanced greatly by an increase in magnetic field intensity. The results suggest that a membrane oxygenator works as an actuator and there is a possibility of self-circulation of blood through an oxygenator in a non-uniform magnetic field. - Highlights: • Effects of a gradient magnetic field on erythrocytes in an oxygenator were analyzed. • Blood changes magnetic susceptibility depending on if it is carrying oxygen or not. • Oxygenation of deoxygenated blood is effective for pressure rise in a magnetic field. • A membrane oxygenator works as an actuator. • There is a possibility of self-circulation of blood through an oxygenator

  13. Numerical analysis of the effects of a high gradient magnetic field on flowing erythrocytes in a membrane oxygenator

    Energy Technology Data Exchange (ETDEWEB)

    Mitamura, Yoshinori, E-mail: ymitamura@par.odn.ne.jp; Okamoto, Eiji, E-mail: okamoto@tspirit.tokai-u.jp

    2015-04-15

    This study was carried out to clarify the effect of a high gradient magnetic field on pressure characteristics of blood in a hollow fiber membrane oxygenator in a solenoid coil by means of numerical analysis. Deoxygenated erythrocytes are paramagnetic, and oxygenated erythrocytes are diamagnetic. Blood changes its magnetic susceptibility depending on whether it is carrying oxygen or not. Motion of blood was analyzed by solving the continuous equation and the Navier–Stokes equation. It was confirmed that oxygenation of deoxygenated blood in the downstream side of the applied magnetic field was effective for pressure rise in a non-uniform magnetic field. The pressure rise was enhanced greatly by an increase in magnetic field intensity. The results suggest that a membrane oxygenator works as an actuator and there is a possibility of self-circulation of blood through an oxygenator in a non-uniform magnetic field. - Highlights: • Effects of a gradient magnetic field on erythrocytes in an oxygenator were analyzed. • Blood changes magnetic susceptibility depending on if it is carrying oxygen or not. • Oxygenation of deoxygenated blood is effective for pressure rise in a magnetic field. • A membrane oxygenator works as an actuator. • There is a possibility of self-circulation of blood through an oxygenator.

  14. Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

    Science.gov (United States)

    Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

    2018-04-01

    Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

  15. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

    Full Text Available A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs thin film coated yttria-stabilized zirconia (YSZ substrate. The thin film was prepared by radio frequency (r.f. magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM and scanning electron microscopy (SEM. X-ray diffraction (XRD patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  16. Thin film oxygen partial pressure sensor

    Science.gov (United States)

    Wortman, J. J.; Harrison, J. W.; Honbarrier, H. L.; Yen, J.

    1972-01-01

    The development is described of a laboratory model oxygen partial pressure sensor using a sputtered zinc oxide thin film. The film is operated at about 400 C through the use of a miniature silicon bar. Because of the unique resistance versus temperature relation of the silicon bar, control of the operational temperature is achieved by controlling the resistance. A circuit for accomplishing this is described. The response of sputtered zinc oxide films of various thicknesses to oxygen, nitrogen, argon, carbon dioxide, and water vapor caused a change in the film resistance. Over a large range, film conductance varied approximately as the square root of the oxygen partial pressure. The presence of water vapor in the gas stream caused a shift in the film conductance at a given oxygen partial pressure. A theoretical model is presented to explain the characteristic features of the zinc oxide response to oxygen.

  17. Lifetime of the internal reference oxygen sensor

    DEFF Research Database (Denmark)

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2013-01-01

    The internal reference oxygen sensor (IROS) based on a binary mixture of metal and its stoichiometric oxide is subject to leaks that result in consumption of the binary mixture. An IROS loses the functionality when the binary mixture is exhausted. Among the possible leak sources the electronic leak...

  18. Oxygen-Partial-Pressure Sensor for Aircraft Oxygen Mask

    Science.gov (United States)

    Kelly, Mark; Pettit, Donald

    2003-01-01

    A device that generates an alarm when the partial pressure of oxygen decreases to less than a preset level has been developed to help prevent hypoxia in a pilot or other crewmember of a military or other high-performance aircraft. Loss of oxygen partial pressure can be caused by poor fit of the mask or failure of a hose or other component of an oxygen distribution system. The deleterious physical and mental effects of hypoxia cause the loss of a military aircraft and crew every few years. The device is installed in the crewmember s oxygen mask and is powered via communication wiring already present in all such oxygen masks. The device (see figure) includes an electrochemical sensor, the output potential of which is proportional to the partial pressure of oxygen. The output of the sensor is amplified and fed to the input of a comparator circuit. A reference potential that corresponds to the amplified sensor output at the alarm oxygen-partial-pressure level is fed to the second input of the comparator. When the sensed partial pressure of oxygen falls below the minimum acceptable level, the output of the comparator goes from the low state (a few millivolts) to the high state (near the supply potential, which is typically 6.8 V for microphone power). The switching of the comparator output to the high state triggers a tactile alarm in the form of a vibration in the mask, generated by a small 1.3-Vdc pager motor spinning an eccentric mass at a rate between 8,000 and 10,000 rpm. The sensation of the mask vibrating against the crewmember s nose is very effective at alerting the crewmember, who may already be groggy from hypoxia and is immersed in an environment that is saturated with visual cues and sounds. Indeed, the sensation is one of rudeness, but such rudeness could be what is needed to stimulate the crewmember to take corrective action in a life-threatening situation.

  19. Label-free sensor for automatic identification of erythrocytes using digital in-line holographic microscopy and machine learning.

    Science.gov (United States)

    Go, Taesik; Byeon, Hyeokjun; Lee, Sang Joon

    2018-04-30

    Cell types of erythrocytes should be identified because they are closely related to their functionality and viability. Conventional methods for classifying erythrocytes are time consuming and labor intensive. Therefore, an automatic and accurate erythrocyte classification system is indispensable in healthcare and biomedical fields. In this study, we proposed a new label-free sensor for automatic identification of erythrocyte cell types using a digital in-line holographic microscopy (DIHM) combined with machine learning algorithms. A total of 12 features, including information on intensity distributions, morphological descriptors, and optical focusing characteristics, is quantitatively obtained from numerically reconstructed holographic images. All individual features for discocytes, echinocytes, and spherocytes are statistically different. To improve the performance of cell type identification, we adopted several machine learning algorithms, such as decision tree model, support vector machine, linear discriminant classification, and k-nearest neighbor classification. With the aid of these machine learning algorithms, the extracted features are effectively utilized to distinguish erythrocytes. Among the four tested algorithms, the decision tree model exhibits the best identification performance for the training sets (n = 440, 98.18%) and test sets (n = 190, 97.37%). This proposed methodology, which smartly combined DIHM and machine learning, would be helpful for sensing abnormal erythrocytes and computer-aided diagnosis of hematological diseases in clinic. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Oxygen consumption in Plasmodium berghei-infected murine red cells: a direct spectrophotometric assay in intact erythrocytes.

    Science.gov (United States)

    Deslauriers, R; Moffatt, D J; Smith, I C

    1986-05-29

    A spectrophotometric assay has been devised to measure oxygen consumption non-invasively in intact murine red cells parasitized by Plasmodium berghei. The method uses oxyhemoglobin in the erythrocytes both as a source of oxygen and as an indicator of oxygen consumption. Spectra of intact cells show broad peaks and sloping baselines due to light-scattering. In order to ascertain the number of varying components in the 370-450 nm range, the resolution of the spectra was enhanced using Fourier transforms of the frequency domain spectra. Calculation of oxygen consumption was carried out for two-component systems (oxyhemoglobin, deoxyhemoglobin) using absorbances at 415 and 431 nm. Samples prepared from highly parasitized mice (greater than 80% parasitemia, 5% hematocrit) showed oxygen consumption rates of (4-8) X 10(-8) microliter/cell per h. This rate was not attributable to the presence of white cells or reticulocytes. The rate of oxygen consumption in the erythrocytes is shown to be modulated by various agents: the respiratory inhibitors NaN3 and KCN (1 mM) reduced oxygen consumption 2-3-fold; salicylhydroxamic acid (2.5 mM) caused a 20% reduction in rate and 10 mM NaN3, completely blocked deoxygenation. Antimalarial drugs and metal-chelating agents were also tested. Chloroquine, EDTA and desferal (desferoxamine mesylate) did not decrease the deoxygenation rate of hemoglobin in parasitized cells. Quinacrine, quinine and primaquine reduced the rate of formation of deoxyhemoglobin but also produced substantial quantities of methemoglobin. The lipophilic chelator, 5-hydroxyquinoline, decreased the rate of deoxygenation one-third. The spectrophotometric assay provides a convenient means to monitor oxygen consumption in parasitized red cells, to test the effects of various agents thereon, and potentially to explore possible mechanisms for oxygen utilization.

  1. Internal-reference solid-electrolyte oxygen sensor

    International Nuclear Information System (INIS)

    Haaland, D.M.

    1977-01-01

    A new solid-electrolyte oxygen sensor has been developed that eliminates the conventional oxygen reference in previous solid-electrolyte oxygen sensor designs and is, therefore, ideally suited as an insertion device for remote oxygen monitoring applications. It is constructed with two cells of stabilized zirconia sealed into a small unit using a new high-temperature platinum-zirconia seal. One electrochemical cell monitors the ratio of oxygen partial pressures inside and outside the sensor while the other solid-electrolyte cell is used for quantitative electrochemical pumping of oxygen. The internal oxygen reference is generated by initially pumping all oxygen out of the known internal volume of the sensor and then quantitatively pumping oxygen back in until oxygen partial pressures are equal inside and out. This information is used with the ideal gas law to calculate oxygen partial pressures. Tests were conducted from 400 to 1000 0 C in mixtures of oxygen and nitrogen spanning approximately 0.2 to 21 percent oxygen concentration range. Sensors with sputtered platinum and porous platinum paste electrodes were compared

  2. A fibre optic oxygen sensor for monitoring of human breathing

    Science.gov (United States)

    Chen, Rongsheng; Farmery, Andrew D.; Chen, Rui; Hahn, Clive E. W.

    2011-11-01

    A reliable and cost effective fibre optic oxygen sensor for monitoring of human breathing has been developed using a normal 200μm silica core/silica cladding optical fibre and a polymer sensing matrix. The fibre optic oxygen sensor is based on the fluorescence quenching of a fluorophore by oxygen. The sensing matrix, containing immobilized Pt(II) complexes, was coated at the end of the silica core/silica cladding optical fibre. The sensitivity and time response of the sensor were evaluated using the method of luminescence lifetime measurement. The polymer substrate influence on the time response of the sensor was improved by using a fibre taper design, and the response time of the optimized sensor was less than 200ms. This silica fibre based optic oxygen sensor is suitable for monitoring of patient breathing in intensive care unit in terms of safety and low cost.

  3. Band 3 protein function in teleost fish erythrocytes: effect of oxygenation-deoxygenation

    Czech Academy of Sciences Publication Activity Database

    Russo, A.; Tellone, E.; Ficarra, S.; Giardina, B.; Bellocco, E.; Lagana, G.; Leuzzi, U.; Kotyk, Arnošt; Galtieri, A.

    2008-01-01

    Roč. 57, č. 1 (2008), s. 49-54 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z50110509 Keywords : erythrocytes * hemoglobin * band 3 protein Subject RIV: CE - Biochemistry Impact factor: 1.653, year: 2008

  4. An oxygen pressure sensor using surface acoustic wave devices

    Science.gov (United States)

    Leighty, Bradley D.; Upchurch, Billy T.; Oglesby, Donald M.

    1993-01-01

    Surface acoustic wave (SAW) piezoelectric devices are finding widespread applications in many arenas, particularly in the area of chemical sensing. We have developed an oxygen pressure sensor based on coating a SAW device with an oxygen binding agent which can be tailored to provide variable sensitivity. The coating is prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer which is then sprayed onto the surface of the SAW device. Experimental data shows the feasibility of tailoring sensors to measure the partial pressure of oxygen from 2.6 to 67 KPa (20 to 500 torr). Potential applications of this technology are discussed.

  5. Precision remote sensor for oxygen and carbon dioxide, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Mesa Photonics proposes development of a passive optical sensor for simultaneous high-precision measurement of oxygen and carbon dioxide profiles within the full...

  6. A fibre-optic oxygen sensor for monitoring human breathing

    International Nuclear Information System (INIS)

    Chen, Rongsheng; Formenti, Federico; Hahn, Clive E W; Farmery, Andrew D; Obeid, Andy

    2013-01-01

    The development and construction of a tapered-tip fibre-optic fluorescence based oxygen sensor is described. The sensor is suitable for fast and real-time monitoring of human breathing. The sensitivity and response time of the oxygen sensor were evaluated in vitro with a gas pressure chamber system, where oxygen partial pressure was rapidly changed between 5 and 15 kPa, and then in vivo in five healthy adult participants who synchronized their breathing to a metronome set at 10, 20, 30, 40, 50, and 60 breaths min –1 . A Datex Ultima medical gas analyser was used to monitor breathing rate as a comparator. The sensor's response time in vitro was less than 150 ms, which allows accurate continuous measurement of inspired and expired oxygen pressure. Measurements of breathing rate by means of our oxygen sensor and of the Datex Ultima were in strong agreement. The results demonstrate that the device can reliably resolve breathing rates up to 60 breaths min –1 , and that it is a suitable cost-effective alternative for monitoring breathing rates and end-tidal oxygen partial pressure in the clinical setting. The rapid response time of the sensor may allow its use for monitoring rapid breathing rates as occur in children and the newborn. (note)

  7. Calibration Of Partial-Pressure-Of-Oxygen Sensors

    Science.gov (United States)

    Yount, David W.; Heronimus, Kevin

    1995-01-01

    Report and analysis of, and discussion of improvements in, procedure for calibrating partial-pressure-of-oxygen sensors to satisfy Spacelab calibration requirements released. Sensors exhibit fast drift, which results in short calibration period not suitable for Spacelab. By assessing complete process of determining total drift range available, calibration procedure modified to eliminate errors and still satisfy requirements without compromising integrity of system.

  8. Thin film devices used as oxygen partial pressure sensors

    Science.gov (United States)

    Canady, K. S.; Wortman, J. J.

    1970-01-01

    Electrical conductivity of zinc oxide films to be used in an oxygen partial pressure sensor is measured as a function of temperature, oxygen partial pressure, and other atmospheric constituents. Time response following partial pressure changes is studied as a function of temperature and environmental changes.

  9. Surface acoustic wave oxygen pressure sensor

    Science.gov (United States)

    Oglesby, Donald M. (Inventor); Upchurch, Billy T. (Inventor); Leighty, Bradley D. (Inventor)

    1994-01-01

    A transducer for the measurement of absolute gas-state oxygen pressure from pressures of less than 100 Pa to atmospheric pressure (1.01 x 10(exp 5) Pa) is based on a standard surface acoustic wave (SAW) device. The piezoelectric material of the SAW device is coated with a compound which will selectively and reversibly bind oxygen. When oxygen is bound by the coating, the mass of the coating increases by an amount equal to the mass of the bound oxygen. Such an increase in the mass of the coating causes a corresponding decrease in the resonant frequency of the SAW device.

  10. Development of oxygen sensors for use in liquid metal

    International Nuclear Information System (INIS)

    Van Nieuwenhove, Rudi; Ejenstam, Jesper; Szakalos, Peter

    2015-01-01

    For generation IV reactor concepts, based on liquid metal cooling, there is a need for robust oxygen sensors which can be used in the core of the reactor since corrosion can only be kept sufficiently low by controlling the dissolved oxygen content in the liquid metal. A robust, ceramic membrane type sensor has been developed at IFE/Halden (Norway) and tested in an autoclave system at KTH (Sweden). The sensor has been tested in lead-bismuth at 550 deg. C and performed well. (authors)

  11. Development of oxygen sensors for use in liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Van Nieuwenhove, Rudi [Institutt for Energiteknikk, Halden, (Norway); Ejenstam, Jesper; Szakalos, Peter [KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Stockholm, (Sweden)

    2015-07-01

    For generation IV reactor concepts, based on liquid metal cooling, there is a need for robust oxygen sensors which can be used in the core of the reactor since corrosion can only be kept sufficiently low by controlling the dissolved oxygen content in the liquid metal. A robust, ceramic membrane type sensor has been developed at IFE/Halden (Norway) and tested in an autoclave system at KTH (Sweden). The sensor has been tested in lead-bismuth at 550 deg. C and performed well. (authors)

  12. Decreased Oxygen Transfer Capacity of Erythrocytes as a Cause of 5-Fluorouracil Related Ischemia

    Directory of Open Access Journals (Sweden)

    Ivan Spasojević

    2008-12-01

    Full Text Available cisplatin have similar effects on the erythrocyte membrane, thus eliminating those changes as a potential source of cardiotoxicity. On the contrary, 31P-NMR and polarography showed that the effects of these cytostatics on the intracellular milieu differ significantly. 5-FU provoked a pronounced decrease of the O2 level in blood and affected the metabolism of phosphate compounds, while cisplatin had no such effects. When combined these two drugs showed synergistic effects, which matches the higher frequency of cardiotoxicity of the combination relative to the sole application of 5-FU. Preliminary results acquired on blood of patients receiving cisplatin/5-FU therapy verified observations obtained ex vivo. These results open a possibility of applying NMR in preclinical trials of new drugs in order to predict their ischemic potential.

  13. Theory and development of fluorescence-based optochemical oxygen sensors: oxygen optodes.

    Science.gov (United States)

    Opitz, N; Lübbers, D W

    1987-01-01

    As the preceding considerations concerning the physical and technical features of oxygen optodes have demonstrated, fluorescence-based optochemical oxygen sensors possess certain advantages and peculiarities compared to conventionally applied electrochemical sensors such as polarographic oxygen electrodes. First, in contrast to oxygen electrodes, oxygen measurements with oxygen optodes do not suffer from distortions caused by the reference electrodes. In addition, because of the polarographic process, platinum electrodes continuously consume oxygen, which falsifies the results, especially when small sample volumes or long-term measurements, or both, are involved, whereas the sensor layer of oxygen optodes must only be equilibrated. Moreover, the surface of the platinum wire has to be catalytically clean in order to obtain a plateau of the polarogram and, consequently, to achieve a low rest current at zero PO2. Unfortunately, the demand for catalytically clean platinum surfaces turns out to be rather critical, since surface contamination occurs even with membranized electrodes, resulting in the well-known phenomenon of "electrode poisoning." The question of the specificity of oxygen electrodes also must be considered. In this context, CO2 and halothane may interfere with oxygen measurements, whereas fluorescence quenching is unaffected by CO2 and halothane affects the measurements only slightly, depending on the special indicator used. Furthermore, because of the flow dependence, oxygen measurements with the oxygen electrode show a distinct "stirring effect" caused by the turbulence in front of the electrode, which disturbs the diffusion field. Because of the completely different physical principle of fluorescence optical sensors, such influences are not observed with oxygen optodes. In addition, isolation and shielding of electrical circuits found in electrodes are not necessary for optodes. Furthermore, the sensitivity of oxygen optodes can be tuned to the desired

  14. Filterability of freshly-collected sickle erythrocytes under venous oxygen pressure without exposure to air.

    Science.gov (United States)

    Shah, Siddharth; Acholonu, Rhonda Graves; Ohene-Frempong, Kwaku; Asakura, Toshio

    2015-12-01

    We previously found that blood samples collected from steady-state patients with sickle cell disease (SCD) without exposure to air contain a new type of reversibly sickled cells (RSCs) with blunt edges at a level of as high as 78%. Since partial oxygenation of once-deoxygenated sickled cells with pointy edges to near venous oxygen pressure generates similar sickled cells with blunt edges in vitro, we named them as partially oxygenated sickled cells (POSCs). On the other hand, partial deoxygenation of once-oxygenated SS cells to venous oxygen pressure generates partially deoxygenated sickled cells (PDSCs) with pointy edges. In this study, we obtained blood samples from 6 steady-state patients with SCD under venous oxygen pressure without exposure to air, subjected them to various oxygenation/deoxygenation/reoxygenation cycles, and studied their filterability through a membrane filter with pore diameter of 3μm, the theoretical minimum diameter of a capillary. Our results indicated that discocytes, POSCs with blunt edges, and irreversibly sickled cells could deform and pass through the filter, while PDSCs with pointy edges were rigid and could not. The filterability of SS cells seems to be related to the length and amount of deoxy-hemoglobin S fibers in the cells. Copyright © 2015. Published by Elsevier Inc.

  15. Oxygen partial pressure sensor for gases

    International Nuclear Information System (INIS)

    Barbero, J.A.; Azcona, M.A.; Orce, A.

    1997-01-01

    Precise measurement of very low oxygen partial pressure is important in both laboratories and industries. Particularly in nuclear industry, it is relevant in the different steps of the nuclear fuel fabrication. It is presented an instrument which is handy and of easy construction, suitable for the measurement of oxygen partial pressure of gases, in the range of 10 -6 -1 atm. It is based on a solid electrolyte galvanic cell, using Yttria doped zirconia as a ceramic membrane. Through an indirect measurement and calibration, the instrument can be used to measure the content of free oxygen in liquids. It is a import feature in NPP instrumentation. The equipment was calibrated with mixtures of special nonreactive gases. (author). 5 refs

  16. Oxygen partial pressure sensor for gases

    Energy Technology Data Exchange (ETDEWEB)

    Barbero, J.A.; Azcona, M.A.; Orce, A. [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche

    1997-10-01

    Precise measurement of very low oxygen partial pressure is important in both laboratories and industries. Particularly in nuclear industry, it is relevant in the different steps of the nuclear fuel fabrication. It is presented an instrument which is handy and of easy construction, suitable for the measurement of oxygen partial pressure of gases, in the range of 10{sup -6}-1 atm. It is based on a solid electrolyte galvanic cell, using Yttria doped zirconia as a ceramic membrane. Through an indirect measurement and calibration, the instrument can be used to measure the content of free oxygen in liquids. It is a import feature in NPP instrumentation. The equipment was calibrated with mixtures of special nonreactive gases. (author). 5 refs.

  17. Biomedical sensor for transcutaneous oxygen measurements using thick film technology

    OpenAIRE

    Lam, Yu-Zhi (Liza)

    2003-01-01

    The measurement of the partial pressure of oxygen in arterial blood is essential for the analysis of a patient's respiratory condition. There are several commercially available methods and systems to measure this parameter transcutaneously. However, they tend to be cumbersome and costly. To overcome the disadvantages presented, a new type of sensor for transcutaneous blood gas measurement was investigated, employing thick film technology, which is an excellent technique to produce sensors in ...

  18. An electrochemical sensor for monitoring oxygen or hydrogen in water

    International Nuclear Information System (INIS)

    Leitai Yang; Morris, D.R.; Lister, D.H.

    1997-01-01

    Preliminary studies have been done on a simple electrochemical sensor which shows promise as a cheap, robust instrument for measuring dissolved oxygen or hydrogen in water. The sensor is based upon the solid-state electrolyte ''Nafion'' (trade name of perfluorinated sulphonic acid, manufactured by DuPont Inc.). The Nafion was dissolved in a mixture of aliphatic alcohols, made into a slurry with platinum black, and applied to a ∼1 cm-square electrode made of stainless steel gauze. The potential of the electrode was measured relative to a standard calomel electrode (SCE) in acid solutions at room temperature through which mixtures of oxygen and nitrogen or hydrogen and nitrogen were bubbled. The sensor was responsive to the equilibrating gas with good reproducibility. A similar sensor without the Nafion was not at all sensitive to changes in oxygen concentration. The voltage response of the sensor showed non-Nernstian behaviour, which suggests that the electrochemical reactions at the electrode surface are complex. Further testing of the sensor is required to verify its sensitivity and responsiveness in typical reactor coolant chemistries and to demonstrate its durability over a range of temperatures. (author). 4 refs, 4 figs, 1 tab

  19. An electrochemical sensor for monitoring oxygen or hydrogen in water

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Leitai; Morris, D R; Lister, D H [University of New Brunswick, Fredericton (Canada). Dept. of Chemical Engineering

    1997-02-01

    Preliminary studies have been done on a simple electrochemical sensor which shows promise as a cheap, robust instrument for measuring dissolved oxygen or hydrogen in water. The sensor is based upon the solid-state electrolyte ``Nafion`` (trade name of perfluorinated sulphonic acid, manufactured by DuPont Inc.). The Nafion was dissolved in a mixture of aliphatic alcohols, made into a slurry with platinum black, and applied to a {approx}1 cm-square electrode made of stainless steel gauze. The potential of the electrode was measured relative to a standard calomel electrode (SCE) in acid solutions at room temperature through which mixtures of oxygen and nitrogen or hydrogen and nitrogen were bubbled. The sensor was responsive to the equilibrating gas with good reproducibility. A similar sensor without the Nafion was not at all sensitive to changes in oxygen concentration. The voltage response of the sensor showed non-Nernstian behaviour, which suggests that the electrochemical reactions at the electrode surface are complex. Further testing of the sensor is required to verify its sensitivity and responsiveness in typical reactor coolant chemistries and to demonstrate its durability over a range of temperatures. (author). 4 refs, 4 figs, 1 tab.

  20. Influence of gemfibrozil on sulfate transport in human erythrocytes during the oxygenation-deoxygenation cycle

    Czech Academy of Sciences Publication Activity Database

    Tellone, E.; Ficarra, S.; Scatena, R.; Giardina, B.; Kotyk, Arnošt; Russo, A.; Colucci, D.; Bellocco, E.; Lagana, G.; Galtieri, A.

    2008-01-01

    Roč. 57, č. 4 (2008), s. 621-629 ISSN 0862-8408 R&D Projects: GA AV ČR(CZ) 1ET400110403 Institutional research plan: CEZ:AV0Z50110509 Keywords : gemfibrozil * sulfate transport * oxygenation-deoxygenation Subject RIV: CE - Biochemistry Impact factor: 1.653, year: 2008

  1. Dissolved hydrogen and oxygen sensors using semiconductor devices

    International Nuclear Information System (INIS)

    Hara, Nobuyoshi; Sugimoto, Katsuhisa

    1995-01-01

    The concentrations of DH and DO in aqueous solution are the factors that determine the equilibrium potential of hydrogen and oxygen electrode reactions, respectively, and are the quantities which directly related to the rates of hydrogen generation type and oxygen consumption type corrosion reactions, therefore, they have the important meaning in the electrochemistry of corrosion. In the hydrogen injection into BWR cooling water, the concentration of hydrogen must be controlled strictly, accordingly DH and DO sensors and electrochemical potential sensors are required. For the chemical sensors used in reactor cooling water, the perfectly solid state sensors made of high corrosion resistance materials, which are small size and withstand high temperature and high pressure, must be developed. The structure and the characteristics of the semiconductor devices used as gas sensors, and the principles of DH and DO sensors are described. If the idea of porous or discontinuous membrane gate is developed, the ion sensor of solid structure with one-body reference electrode may be made. (K.I.)

  2. Band 3 Erythrocyte Membrane Protein Acts as Redox Stress Sensor Leading to Its Phosphorylation by p72 Syk

    Directory of Open Access Journals (Sweden)

    Antonella Pantaleo

    2016-01-01

    Full Text Available In erythrocytes, the regulation of the redox sensitive Tyr phosphorylation of band 3 and its functions are still partially defined. A role of band 3 oxidation in regulating its own phosphorylation has been previously suggested. The current study provides evidences to support this hypothesis: (i in intact erythrocytes, at 2 mM concentration of GSH, band 3 oxidation, and phosphorylation, Syk translocation to the membrane and Syk phosphorylation responded to the same micromolar concentrations of oxidants showing identical temporal variations; (ii the Cys residues located in the band 3 cytoplasmic domain are 20-fold more reactive than GSH; (iii disulfide linked band 3 cytoplasmic domain docks Syk kinase; (iv protein Tyr phosphatases are poorly inhibited at oxidant concentrations leading to massive band 3 oxidation and phosphorylation. We also observed that hemichromes binding to band 3 determined its irreversible oxidation and phosphorylation, progressive hemolysis, and serine hyperphosphorylation of different cytoskeleton proteins. Syk inhibitor suppressed the phosphorylation of band 3 also preventing serine phosphorylation changes and hemolysis. Our data suggest that band 3 acts as redox sensor regulating its own phosphorylation and that hemichromes leading to the protracted phosphorylation of band 3 may trigger a cascade of events finally leading to hemolysis.

  3. Metabolism of Citrate and Other Carboxylic Acids in Erythrocytes As a Function of Oxygen Saturation and Refrigerated Storage

    Directory of Open Access Journals (Sweden)

    Travis Nemkov

    2017-10-01

    Full Text Available State-of-the-art proteomics technologies have recently helped to elucidate the unanticipated complexity of red blood cell metabolism. One recent example is citrate metabolism, which is catalyzed by cytosolic isoforms of Krebs cycle enzymes that are present and active in mature erythrocytes and was determined using quantitative metabolic flux analysis. In previous studies, we reported significant increases in glycolytic fluxes in red blood cells exposed to hypoxia in vitro or in vivo, an observation relevant to transfusion medicine owing to the potential benefits associated with hypoxic storage of packed red blood cells. Here, using a combination of steady state and quantitative tracing metabolomics experiments with 13C1,2,3-glucose, 13C6-citrate, 13C515N2-glutamine, and 13C1-aspartate via ultra-high performance liquid chromatography coupled on line with mass spectrometry, we observed that hypoxia in vivo and in vitro promotes consumption of citrate and other carboxylates. These metabolic reactions are theoretically explained by the activity of cytosolic malate dehydrogenase 1 and isocitrate dehydrogenase 1 (abundantly represented in the red blood cell proteome, though moonlighting functions of additional enzymes cannot be ruled out. These observations enhance understanding of red blood cell metabolic responses to hypoxia, which could be relevant to understand systemic physiological and pathological responses to high altitude, ischemia, hemorrhage, sepsis, pulmonary hypertension, or hemoglobinopathies. Results from this study will also inform the design and testing of novel additive solutions that optimize red blood cell storage under oxygen-controlled conditions.

  4. Retrievable micro-inserts containing oxygen sensors for monitoring tissue oxygenation using EPR oximetry

    International Nuclear Information System (INIS)

    Dinguizli, M; Beghein, N; Gallez, B

    2008-01-01

    Tissue oxygenation is a crucial parameter in various physiopathological situations and can influence the therapeutic response of tumours. EPR oximetry is a reliable method for assessing and monitoring oxygen levels in vivo over long periods of time. Among the different paramagnetic oxygen sensors available for EPR oximetry, lithium phthalocyanine (LiPc) is a serious candidate for in vivo applications because of its narrow linewidth and its high signal-to-noise ratio. To enhance the biocompatibility of the sensors, fluoropolymer Teflon AF2400 was used to make cylindrical micro-inserts containing LiPc crystals. This new micro-pellet design has several advantages for in vivo studies, including the possibility of being able to choose the implant size, a high sensor content, the facility of in vivo insertion and complete protection with preservation of the oxygen sensor's characteristics. The response to oxygen and the kinetics of this response were tested using in vivo EPR: no differences were observed between micro-inserts and uncoated LiPc crystals. Pellets implanted in vivo in muscles conserved their responsiveness over a long period of time (∼two months), which is much longer than the few days of stability observed using LiPc crystals without protection by the implant. Finally, evaluation of the biocompatibility of the implants revealed no inflammatory reaction around the implantation area

  5. Development of oxygen sensing technology in an irradiated fuel rod. Characteristic test of oxygen sensor

    International Nuclear Information System (INIS)

    Saito, Junichi; Hoshiya, Taiji; Sakurai, Fumio; Sakai, Haruyuki

    1996-03-01

    At the Department of JMTR (Japan Materials Test Reactor), the re-instrumentation technologies to a high burnup fuel rod irradiated in an LWR have been developed to study irradiation behavior of the fuel during power transient. It has been progressed developing a chemical sensor as one of the re-instrumentation technologies. This report summarizes the results of characteristic tests of an oxygen sensor made of Yttria Stabilized Zirconia (YSZ) as a solid electrolyte. Several kinds of experiments were carried out to evaluate the electromotive force (emf) performance, stability and lifetime of the oxygen sensor with Ni/NiO, Cr/Cr 2 O 3 and Fe/FeO, respectively as a reference electrode. From the experimental data, it is suggested that the reference electrode of Ni/NiO reveals the most appropriate characteristic of the sensor to measure the partial oxygen pressure in a fuel rod. It is the final goal of this development to clarify the change of oxygen chemical potential in a fuel rod during power transient. (author)

  6. Improved Internal Reference Oxygen Sensors with Composite Ceramic Electrodes

    DEFF Research Database (Denmark)

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2012-01-01

    Potentiometric oxygen sensors with an internal reference electrode, which uses the equilibrium pO2 of the binary mixture of Ni/NiO as the reference, are demonstrated. The cells employ Pt or composite ceramics as the sensing electrode. The cells are fabricated by a flexible and potentially low cost...... and performance are highly reproducible. The composite ceramics, based on strontium doped manganite and yttria doped zirconia, are proven superior over Pt to serve as the electrode material....

  7. Contact CMOS imaging of gaseous oxygen sensor array.

    Science.gov (United States)

    Daivasagaya, Daisy S; Yao, Lei; Yi Yung, Ka; Hajj-Hassan, Mohamad; Cheung, Maurice C; Chodavarapu, Vamsy P; Bright, Frank V

    2011-10-01

    We describe a compact luminescent gaseous oxygen (O 2 ) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O 2 -sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp) 3 ] 2+ ) encapsulated within sol-gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 µW and an average dynamic power of 625 µW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors.

  8. Improved Internal Reference Oxygen Sensors Using Composite Oxides as Electrodes

    DEFF Research Database (Denmark)

    Hu, Qiang

    The thesis describes the research on and development of an internal reference oxygen sensor (IROS). The IROS is potentiometric and uses the equilibrium pO2of the binary mixture of Ni/NiO as the reference pO2. The sensing electrode of the IROS are made from metallic Pt or the composite of (La0.75S...... the application of IROSes are provided. Based on the concepts and fundamentals of the IROS, internal reference sensors that detect other gas species such as hydrogen, chlorine and bromine may be developed.......The thesis describes the research on and development of an internal reference oxygen sensor (IROS). The IROS is potentiometric and uses the equilibrium pO2of the binary mixture of Ni/NiO as the reference pO2. The sensing electrode of the IROS are made from metallic Pt or the composite of (La0.75Sr0...... from 8YSZ is evaluated quantitatively and figures that may be used to design the depletion period of an IROS due to the electronic leak of 8YSZ are provided. One dimensional numerical simulations are performed to study the variation in cell voltage during the process of gas mixing, and the asymmetric...

  9. Development of Selective Excitation Methods in Nuclear Magnetic Resonance: Investigation of Hemoglobin Oxygenation in Erythrocytes Using Proton and Phosphorus -31 Nuclear Magnetic Resonance

    Science.gov (United States)

    Fetler, Bayard Keith

    1993-01-01

    Nuclear magnetic resonance (NMR) offers a potential method for making measurements of the percent oxygenation of hemoglobin (Hb) in living tissue non-invasively. As a demonstration of the feasibility of such measurements, we measured the percent oxygenation of Hb in red blood cells (erythrocytes) using resonances in the proton-NMR (^1H-NMR) spectrum which are characteristic of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb), and are due to the unique magnetic properties of these molecules. To perform these measurements, we developed a new NMR method of selectively exciting signals in a region of interest with uniform phase and amplitude, while suppressing the signal of the water resonance. With this method, we are able to make exact calculations distinguishing between uniform phase excitation produced at large flip-angles using the non-linear properties of the Bloch equations, and uniform phase excitation produced at small flip-angles using asymmetric pulse excitation functions. We measured the percent oxygenation of three characteristic ^1H-NMR resonances of Hb: two from deoxy-Hb, originating from the N_delta H protons of histidine residue F8, which occur at different frequencies for the alpha and beta chains of Hb; and one from oxy-Hb, originating from the gamma_2 -CH_3 protons of valine residue E11. We performed experiments both on fresh erythrocytes and on erythrocytes depleted of 2,3-diphosphoglycerate (2,3-DPG), and found that oxygen is more tightly bound to Hb in the former case. In both fresh and 2,3-DPG-depleted samples, we found that: (i) from the deoxy-Hb marker resonances, there is a small but significant difference in the oxygen saturation between the alpha and beta chains; (ii) the decrease in the areas of the deoxy-Hb marker resonances correlates well with the increase in the percent oxygenation of Hb as measured optically; (iii) the area of the oxy-Hb marker resonance may be up to ~15% less than the optically measured Hb saturation. We are

  10. About Error in Measuring Oxygen Concentration by Solid-Electrolyte Sensors

    Directory of Open Access Journals (Sweden)

    V. I. Nazarov

    2008-01-01

    Full Text Available The paper evaluates additional errors while measuring oxygen concentration in a gas mixture by a solid-electrolyte cell. Experimental dependences of additional errors caused by changes in temperature in a sensor zone, discharge of gas mixture supplied to a sensor zone, partial pressure in the gas mixture and fluctuations in oxygen concentrations in the air.

  11. Online analysis of oxygen inside silicon-glass microreactors with integrated optical sensors

    DEFF Research Database (Denmark)

    Ehgartner, Josef; Sulzer, Philipp; Burger, Tobias

    2016-01-01

    A powerful online analysis set-up for oxygen measurements within microfluidic devices is presented. It features integration of optical oxygen sensors into microreactors, which enables contactless, accurate and inexpensive readout using commercially available oxygen meters via luminescent lifetime...... monitoring of enzyme transformations, including d-alanine or d-phenylalanine oxidation by d-amino acid oxidase, and glucose oxidation by glucose oxidase....

  12. Expression of inducible nitric oxide synthase, caspase-3 and production of reactive oxygen intermediate on endothelial cells culture (HUVECs treated with P. falciparum infected erythrocytes and tumour necrosis factor-α

    Directory of Open Access Journals (Sweden)

    Loeki E. Fitri

    2006-09-01

    Full Text Available Cytoadherence of P. falciparum infected erythrocytes on endothelial cells is a key factor in development of severe malaria. This process may associated with the activation of local immune that was enhanced by tumour necrosis factor-α (TNF-α. This study was conducted to see the influence of P.falciparum infected erythrocytes cytoadherence and TNF-α treatment in inducing endothelial cells activation in vitro. inducible nitric oxide synthase (iNOS and caspase-3 expression, also reactive oxygen intermediate (ROI production were used as parameters. An Experimental laboratory study had been done to observe endothelial cells activation (HUVECs after treatment with TNF-α for 20 hours or P. falciparum infected erythrocytes for 1 hour or both of them. Normal endothelial cells culture had been used as a control. Using immunocytochemistry local immune activation of endothelial cells was determined by iNOS and caspase-3 expression. Nitro Blue Tetrazolium reduction-assay was conducted to see the ROI production semi quantitatively. inducible nitric oxide synthase expression only found on endothelial cells culture treated with P. falciparum infected erythrocytes or both P. falciparum infected erythrocytes and TNF-α. Caspase-3 expression found slightly on normal endothelial cells culture. This expression increased significantly on endothelial cells culture treated with both P.falciparum infected erythrocytes and TNF-α (p=0.000. The normal endothelial cells release low level of ROI in the presence of non-specific trigger, PMA. In the presence of P. falciparum infected erythrocytes or TNF-α or both of them, some cells showed medium to high levels of ROI. Cytoadherence of P. falciparum infected erythrocytes and TNF α treatment on endothelial cells can induce activation of local immune marked by increase inducible nitric oxide synthase and release of free radicals that cause cell damage. (Med J Indones 2006; 15:151-6 Keywords: P.falciparum ,HUVECs, TNF-α, i

  13. Oxygen sensor development and low temperature corrosion study in lead-alloy coolant loop

    International Nuclear Information System (INIS)

    Hwang, Il Soon; Bahn, Chi Bum; Lee, Seung Gi; Jeong, Seung Ho; Nam, Hyo On; Lim, Jun

    2007-07-01

    Oxygen sensor to measure dissolved oxygen concentration at liquid lead-bismuth eutectic environments have been developed. Developed oxygen sensor for application in lead-bismuth eutectic (LBE) system was based on the oxygen ion conductor made of YSZ ceramic having Bi/Bi2O3 reference joined by electro-magnetic swaging. Leakage problem, which was major problem of existing sensors, can be solved by using electro-magnetic swaging method. A new calibration strategy combining the oxygen titration with electrochemical impedance spectroscopy (EIS) was performed to increase the reliability of sensor. Another calibration was also conducted by controlling the oxygen concentration using OCS (oxygen control system). Materials corrosion tests of various metals (SS316, EP823, T91 and HT9) were conducted for up to 1,000 hours with specimen inspection after every 333hours at 450 .deg. C in HELIOS. Oxygen concentration was controlled at 10 -6 wt% by using the direct gas bubbling of Ar+4%H 2 , Ar+5%O 2 and pure Ar. The dissolved oxygen concentration in LBE was also monitored by two calibrated YSZ oxygen sensors located at different places under different temperatures within HELIOS. It shows a good performance during 1000 hours. Liquid metal embrittlement (LME) test of SS316L specimen in the LBE was performed at various temperature and strain rate. The result shows that the liquid metal embrittlement effect is not crucial at tested conditions

  14. Oxygen sensors for Heavy Liquid Metal coolants: Calibration and assessment of the minimum reading temperature

    Energy Technology Data Exchange (ETDEWEB)

    Bassini, S., E-mail: serena.bassini@enea.it; Antonelli, A.; Di Piazza, I.; Tarantino, M.

    2017-04-01

    Oxygen sensors for Heavy Liquid Metals (HLMs) such as lead and LBE (lead-bismuth eutectic) will be essential devices in future Lead Fast Reactor (LFR) and Accelerator Driven System (ADS). Potentiometric sensors based on solid electrolytes were developed in recent years to this purpose. Internal reference electrodes such as Pt-air and Bi/Bi{sub 2}O{sub 3} liquid metal/metal-oxide are among the most used but they both have a weak point: Pt-air sensor has a high minimum reading temperature around 400 °C whereas Bi/Bi{sub 2}O{sub 3} suffers from internal stresses induced by Bi volume variations with temperature, which may lead to the sensor failure in the long-term. The present work describes the performance of standard Pt-air and Bi/Bi{sub 2}O{sub 3} sensors and compares them with recent Cu/Cu{sub 2}O sensor. Sensors with Yttria Partially Stabilized Zirconia (YPSZ) electrolyte were calibrated in oxygen-saturated HLM between 160 and 550 °C and the electric potential compared to the theoretical one to define the accuracy and the minimum reading temperature. Standard Pt-air sensor were also tested using Yttria Totally Stabilized Zirconia (YTSZ) to assess the effect of a different electrolyte on the minimum reading temperature. The performance of Pt-air and Cu/Cu{sub 2}O sensors with YPSZ electrolyte were then tested together in low-oxygen HLM between 200 and 450 °C. The results showed that Pt-air, Bi/Bi{sub 2}O{sub 3} and Cu/Cu{sub 2}O sensors with YPSZ measured oxygen in HLMs down to 400 °C, 290 °C and 200 °C respectively. When the YTSZ electrolyte was used in place of the YPSZ, the Pt-air sensor measured correctly down to at least 350 °C thanks to the superior ionic conductivity of the YTSZ. When Cu/Cu{sub 2}O and Pt-air sensors were tested together in the same low-oxygen HLM between 200 and 450 °C, Cu/Cu{sub 2}O sensor worked predictably in the whole temperature range whereas Pt-air sensor exhibited a correct output only above 400 °C. - Highlights: •Oxygen

  15. Characterization and re-activation of oxygen sensors for use in liquid lead-bismuth

    International Nuclear Information System (INIS)

    Kurata, Yuji; Abe, Yuji; Futakawa, Masatoshi; Oigawa, Hiroyuki

    2010-01-01

    Control of oxygen concentration in liquid lead-bismuth is one of the most important tasks to develop accelerator driven systems. In order to improve the reliability of oxygen sensors, re-activation treatments were investigated as well as characterization of oxygen sensors for use in liquid lead-bismuth. The oxygen sensor with a solid electrolyte of yttria-stabilized zirconia and a Pt/gas reference electrode showed almost the same electromotive force values in gas and liquid lead-bismuth, respectively, as the theoretical ones at temperatures above 400 deg. C or 450 deg. C. After long-term use of 6500 h, the outputs of the sensor became incorrect in liquid lead-bismuth. The state of the sensor that indicated incorrect outputs could not be recovered by cleaning with a nitric acid. However, it was found that the oxygen sensor became a correct sensor indicating theoretical values in liquid lead-bismuth after re-activation by the Pt-treatment of the outer surface of the sensor.

  16. Investigations of a zirconia solid electrolyte oxygen sensor in liquid lead

    Energy Technology Data Exchange (ETDEWEB)

    Rivai, Abu Khalid, E-mail: rivai.abukhalid@jaea.go.j [Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, N1-18, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Takahashi, Minoru, E-mail: mtakahas@nr.titech.ac.j [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-18, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2010-03-15

    Investigations of a magnesia-stabilized zirconia solid electrolyte oxygen sensor for oxygen control measurement in liquid lead were carried out. The fluid of Bi/Bi{sub 2}O{sub 3} as a reference electrode and a molybdenum wire as a working electrode to detect the output signal of the sensor were used. The Nernst equation was used to estimate the electromotive force (EMF) values theoretically. The temperatures of liquid lead were 500, 550 and 600 deg. C. The results showed that the injection gas temperatures did not affect the detected EMF, the sensor responded well to quick changes of oxygen activity in liquid lead, and the discrepancy between the measured and theoretical EMF of the oxygen sensor output signal was higher at 500 deg. C than at 550 and 600 deg. C.

  17. Optical Sensors for Hydrogen and Oxygen for Unambiguous Detection in Their Mutual Presence, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Phase I SBIR project is to develop sensors that can discriminate the presence of combustible gases like oxygen (O2) in hydrogen (H2) or H2 in O2...

  18. Influence of erythrocyte oxygenation and intravascular ATP on resting and exercising skeletal muscle blood flow in humans with mitochondrial myopathy

    DEFF Research Database (Denmark)

    Jeppesen, Tina D; Vissing, John; González-Alonso, José

    2012-01-01

    Oxygen (O(2)) extraction is impaired in exercising skeletal muscle of humans with mutations of mitochondrial DNA (mtDNA), but the muscle hemodynamic response to exercise has never been directly investigated. This study sought to examine the extent to which human skeletal muscle perfusion can incr...

  19. Oxygen optodes as fast sensors for eddy correlation measurements in aquatic systems

    DEFF Research Database (Denmark)

    Chipman, Lindsay; Huettel, Markus; Berg, Peter

    2012-01-01

    The aquatic eddy-correlation technique can be used to noninvasively determine the oxygen exchange across the sediment-water interface by analyzing the covariance of vertical flow velocity and oxygen concentration in a small measuring volume above the sea bed. The method requires fast sensors...... that combine the advantages of noninvasive measurements and integration of fluxes over a large footprint area, using a relatively rugged and less expensive sensor....

  20. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  1. Effect of Humid Aging on the Oxygen Adsorption in SnO₂ Gas Sensors.

    Science.gov (United States)

    Suematsu, Koichi; Ma, Nan; Watanabe, Ken; Yuasa, Masayoshi; Kida, Tetsuya; Shimanoe, Kengo

    2018-01-16

    To investigate the effect of aging at 580 °C in wet air (humid aging) on the oxygen adsorption on the surface of SnO₂ particles, the electric properties and the sensor response to hydrogen in dry and humid atmospheres for SnO₂ resistive-type gas sensors were evaluated. The electric resistance in dry and wet atmospheres at 350 °C was strongly increased by humid aging. From the results of oxygen partial pressure dependence of the electric resistance, the oxygen adsorption equilibrium constants ( K ₁; for O - adsorption, K ₂; for O 2- adsorption) were estimated on the basis of the theoretical model of oxygen adsorption. The K ₁ and K ₂ in dry and wet atmospheres at 350 °C were increased by humid aging at 580 °C, indicating an increase in the adsorption amount of both O - and O 2- . These results suggest that hydroxyl poisoning on the oxygen adsorption is suppressed by humid aging. The sensor response to hydrogen in dry and wet atmosphere at 350 °C was clearly improved by humid aging. Such an improvement of the sensor response seems to be caused by increasing the oxygen adsorption amount. Thus, the humid aging offers an effective way to improve the sensor response of SnO₂ resistive-type gas sensors in dry and wet atmospheres.

  2. Effect of Humid Aging on the Oxygen Adsorption in SnO2 Gas Sensors

    Directory of Open Access Journals (Sweden)

    Koichi Suematsu

    2018-01-01

    Full Text Available To investigate the effect of aging at 580 °C in wet air (humid aging on the oxygen adsorption on the surface of SnO2 particles, the electric properties and the sensor response to hydrogen in dry and humid atmospheres for SnO2 resistive-type gas sensors were evaluated. The electric resistance in dry and wet atmospheres at 350 °C was strongly increased by humid aging. From the results of oxygen partial pressure dependence of the electric resistance, the oxygen adsorption equilibrium constants (K1; for O− adsorption, K2; for O2− adsorption were estimated on the basis of the theoretical model of oxygen adsorption. The K1 and K2 in dry and wet atmospheres at 350 °C were increased by humid aging at 580 °C, indicating an increase in the adsorption amount of both O− and O2−. These results suggest that hydroxyl poisoning on the oxygen adsorption is suppressed by humid aging. The sensor response to hydrogen in dry and wet atmosphere at 350 °C was clearly improved by humid aging. Such an improvement of the sensor response seems to be caused by increasing the oxygen adsorption amount. Thus, the humid aging offers an effective way to improve the sensor response of SnO2 resistive-type gas sensors in dry and wet atmospheres.

  3. Calibration and testing of a polarographic sensor for the measurement of oxygen in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Boniforti, R; Dell' Amico, F; Marri, P

    1987-04-01

    The procedures for the calibration and testing of a polarographic oxygen sensor, mounted on a CTD probe, are reported. As an example of in-field use, oxygen and temperature profiles obtained in Fossa del Pomo (Central Adriatic Sea), are given.

  4. Singlet Oxygen Sensor Green: Photochemical Behavior in Solution and in a Mammalian Cell

    DEFF Research Database (Denmark)

    Gollmer, Anita; Arnbjerg, Jacob; Blaikie, Frances Helen

    2011-01-01

    The development of efficient and selective luminescent probes for reactive oxygen species, particularly for singlet molecular oxygen, is currently of great importance. In this study, the photochemical behavior of Singlet Oxygen Sensor Green® (SOSG), a commercially available fluorescent probe...... of the reaction between SOSG and singlet oxygen is, itself, an efficient singlet oxygen photosensitizer. Second, SOSG appears to efficiently bind to proteins which, in turn, can influence uptake by a cell as well as behavior in the cell. As such, incorrect use of SOSG can yield misleading data on yields...

  5. Development status of oxygen solid electrolyte sensors in HLMC in respect to monoblock reactor facilities

    International Nuclear Information System (INIS)

    Martynov, P.N.; Askhadullin, R.Sh.; Storozhenko, A.N.; Shelemet'ev, V.M.; Sadovnichij, R.P.; Ivanov, I.I.

    2014-01-01

    The results of developing sensors on the base of solid electrolytes to control oxygen in lead and lead-bismuth coolants are considered. It is found out that ceramic detecting elements on the base of solid electrolytes from oxide ceramics are able to work a long time in conditions of high temperatures and thermal shocks in molten metals (in gases). They show stable conducting and mechanical properties, thermal resistance, low gas permeability. Using considered detecting elements different sensors, including ones for monoblock reactors and facilities, are developed and manufactured. The given sensors can be used for both continuous and periodical oxygen control in heavy liquid metal coolants [ru

  6. A new immersion sensor for rapid electrochemical determination of dissolved oxygen in liquid metals

    International Nuclear Information System (INIS)

    Janke, D.; Schwerdtfeger, K.

    1978-01-01

    Development of a new solid electrolyte 'needle sensor' with ZrO 2 or ThO 2 electrolyte and metal-metal oxide reference mixture for the rapid determination of oxygen in steel melts. Details of the manufacture of the layer-structured, miniaturized probe. Test results of simultaneous measurements performed with the newly developed ZrO 2 needle sensor and the hitherto usual tubular sensor in iron melts at oxygen activities between 0.00005 and 0.030. (orig.) [de

  7. Oxygen Optode Sensors: Principle, Characterization, Calibration, and Application in the Ocean

    Directory of Open Access Journals (Sweden)

    Henry C. Bittig

    2018-01-01

    Full Text Available Recently, measurements of oxygen concentration in the ocean—one of the most classical parameters in chemical oceanography—are experiencing a revival. This is not surprising, given the key role of oxygen for assessing the status of the marine carbon cycle and feeling the pulse of the biological pump. The revival, however, has to a large extent been driven by the availability of robust optical oxygen sensors and their painstakingly thorough characterization. For autonomous observations, oxygen optodes are the sensors of choice: They are used abundantly on Biogeochemical-Argo floats, gliders and other autonomous oceanographic observation platforms. Still, data quality and accuracy are often suboptimal, in some part because sensor and data treatment are not always straightforward and/or sensor characteristics are not adequately taken into account. Here, we want to summarize the current knowledge about oxygen optodes, their working principle as well as their behavior with respect to oxygen, temperature, hydrostatic pressure, and response time. The focus will lie on the most widely used and accepted optodes made by Aanderaa and Sea-Bird. We revisit the essentials and caveats of in-situ in air calibration as well as of time response correction for profiling applications, and provide requirements for a successful field deployment. In addition, all required steps to post-correct oxygen optode data will be discussed. We hope this summary will serve as a comprehensive, yet concise reference to help people get started with oxygen observations, ensure successful sensor deployments and acquisition of highest quality data, and facilitate post-treatment of oxygen data. In the end, we hope that this will lead to more and higher-quality oxygen observations and help to advance our understanding of ocean biogeochemistry in a changing ocean.

  8. A plastic optical fiber sensor for the dual sensing of temperature and oxygen

    Science.gov (United States)

    Lo, Yu-Lung; Chu, Chen-Shane

    2008-04-01

    This study presents a low-cost plastic optical fiber sensor for the dual sensing of temperature and oxygen. The sensor features a commercially available epoxy glue coated on the side-polished fiber surface for temperature sensing and a fluorinated xerogel doped with platinum tetrakis pentrafluoropheny porphine (PtTFPP) coated on the fiber end for oxygen sensing. The temperature and oxygen indicators are both excited using a UV LED light source with a wavelength of 380 nm. The luminescence emission spectra of the two indicators are well resolved and exhibit no cross-talk effects. Overall, the results indicate that the dual sensor presented in this study provides an ideal solution for the non-contact, simultaneous sensing of temperature and oxygen in general biological and medical applications.

  9. Effects of palladium coatings on oxygen sensors of titanium dioxide thin films

    International Nuclear Information System (INIS)

    Castaneda, L.

    2007-01-01

    Titanium dioxide (TiO 2 -anatase phase) thin films were deposited by the ultrasonic spray pyrolysis technique employing titanium (IV) oxide acetylacetonate (TiO(acac) 2 ) dissolved in pure methanol as a source material. In order to prepare oxygen sensors, TiO 2 thin films were deposited on interdigitated gold electrodes with contacted alumina substrates. Palladium (Pd) coatings were carried out by vacuum thermal evaporation through a metallic mask. The effect of the surface additive (Pd) on the response of the thin film TiO 2 oxygen sensors was monitored in a mixture with zero-grade air. The electrical characterization (monitoring of the electrical surface resistance with the operation temperature) of the sensors in an atmosphere of oxygen (diluted in zero-grade air) was performed in a vacuum chamber (10 -6 Torr), where the gas pressure can be controlled. The films sensitivity was estimated by the following relation: s=R gas -R 0 /R 0 . The response time of the sensor is defined to be the time needed to reach a 0.9R 0 value when the oxygen excess is removed. The gas-sensing properties of TiO 2 sensors in an atmosphere of 10 4 ppm of oxygen were measured between 100 and 450 deg. C. Experimental results obtained using palladium as a surface additive show that the sensitivity reaches a stationary value of 1.18 for O 2 concentration of 100ppm in zero-grade air at 300 deg. C, which is as high as those reported for oxygen sensors prepared with more expensive and complex techniques. The role and activity of palladium coatings incorporated on solid-state oxygen sensors are determined by their chemical state, aggregation form and interaction with the metal-oxide semiconductor

  10. Pericellular oxygen monitoring with integrated sensor chips for reproducible cell culture experiments.

    Science.gov (United States)

    Kieninger, J; Aravindalochanan, K; Sandvik, J A; Pettersen, E O; Urban, G A

    2014-04-01

    Here we present an application, in two tumour cell lines, based on the Sensing Cell Culture Flask system as a cell culture monitoring tool for pericellular oxygen sensing. T-47D (human breast cancer) and T98G (human brain cancer) cells were cultured either in atmospheric air or in a glove-box set at 4% oxygen, in both cases with 5% CO2 in the gas phase. Pericellular oxygen tension was measured with the help of an integrated sensor chip comprising oxygen sensor arrays. Obtained results illustrate variation of pericellular oxygen tension in attached cells covered by stagnant medium. Independent of incubation conditions, low pericellular oxygen concentration levels, usually associated with hypoxia, were found in dense cell cultures. Respiration alone brought pericellular oxygen concentration down to levels which could activate hypoxia-sensing regulatory processes in cultures believed to be aerobic. Cells in culture believed to experience conditions of mild hypoxia may, in reality, experience severe hypoxia. This would lead to incorrect assumptions and suggests that pericellular oxygen concentration readings are of great importance to obtain reproducible results when dealing with hypoxic and normoxic (aerobic) incubation conditions. The Sensing Cell Culture Flask system allows continuous monitoring of pericellular oxygen concentration with outstanding long-term stability and no need for recalibration during cell culture experiments. The sensor is integrated into the flask bottom, thus in direct contact with attached cells. No additional equipment needs to be inserted into the flask during culturing. Transparency of the electrochemical sensor chip allows optical inspection of cells attached on top of the sensor. © 2014 John Wiley & Sons Ltd.

  11. Development of sensors for monitoring oxygen and free radicals in plant physiology

    Science.gov (United States)

    Chaturvedi, Prachee

    Oxygen plays a critical role in the physiology of photosynthetic organisms, including bioenergetics, metabolism, development, and stress response. Oxygen levels affect photosynthesis, respiration, and alternative oxidase pathways. Likewise, the metabolic rate of spatially distinct plant cells (and therefore oxygen flux) is known to be affected by biotic stress (e.g., herbivory) and environmental stress (e.g., salt/nutrient stress). During aerobic metabolism, cells produce reactive oxygen species (ROS) as a by product. Plants also produce ROS during adaptation to stress (e.g., abscisic acid (ABA) mediated stress responses). If stress conditions are prolonged, ROS levels surpass the capacity of detoxifying mechanisms within the cell, resulting in oxidative damage. While stress response pathways such as ABA-mediated mechanisms have been well characterized (e.g., water stress, inhibited shoot growth, synthesis of storage proteins in seeds), the connection between ROS production, oxygen metabolism and stress response remains unknown. In part, this is because details of oxygen transport at the interface of cell(s) and the surrounding microenvironment remains nebulous. The overall goal of this research was to develop oxygen and Free radical sensors for studying stress signaling in plants. Recent developments in nanomaterials and data acquisition systems were integrated to develop real-time, non-invasive oxygen and Free radical sensors. The availability of these sensors for plant physiologists is an exciting opportunity to probe the functional realm of cells and tissues in ways that were not previously possible.

  12. Molecular mechanisms of erythrocyte photo-irradiation

    International Nuclear Information System (INIS)

    Ferreira, W.T.; Souza, M.C.

    1985-01-01

    The role of singlet oxygen and the lipid peroxidation of erythrocyte membrane are studied. The irradiation of erythrocytes with visible light in the presence of a photodynamic mediator (toluidine blue) is reported. A system of light application by optical fiber, connected to a catheter is suggested for local instillation of the photosensitizing agent. (M.A.C.) [pt

  13. A miniaturized oxygen sensor integrated on fiber surface based on evanescent-wave induced fluorescence quenching

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Yan [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, 610500 (China); Tan, Jun; Wang, Chengjie; Zhu, Ying [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Fang, Shenwen [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, 610500 (China); Wu, Jiayi; Wang, Qing [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Duan, Ming, E-mail: swpua124@126.com [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, 610500 (China)

    2016-11-15

    In this work, a miniaturized sensor was integrated on fiber surface and developed for oxygen determination through evanescent-wave induced fluorescence quenching. The sensor was designed by using light emitting diode (LED) as light source and optical fiber as light transmission element. Tris(2,2′-bipyridyl) ruthenium ([Ru(bpy){sub 3}]{sup 2+}) fluorophore was immobilized in the organically modified silicates (ORMOSILs) film and coated onto the fiber surface. When light propagated by total internal reflection (TIR) in the fiber core, evanescent wave could be produced on the fiber surface and excite [Ru(bpy){sub 3}]{sup 2+} fluorophore to produce fluorescence emission. Then oxygen could be determinated by its quenching effect on the fluorescence and its concentration could be evaluated according to Stern–Volumer model. Through integrating evanescent wave excitation and fluorescence quenching on fiber surface, the sensor was successfully miniaturized and exhibit improved performances of high sensitivity (1.4), excellent repeatability (1.2%) and fast analysis (12 s) for oxygen determination. The sensor provided a newly portable method for in-situ and real-time measurement of oxygen and showed potential for practical oxygen analysis in different application fields. Furthermore, the fabrication of this sensor provides a miniaturized and portable detection platform for species monitoring by simple modular design. - Highlights: • ORMOSILs sensing film immobilized with [Ru(bpy){sub 3}]{sup 2+} fluorophore was coated on fiber surface. • Evanescent wave on the fiber surface was utilized as excitation source to produce fluorescence. • Oxygen was measured based on its quenching effect on evanescent wave-induce fluorescence. • Sensor fabrication was miniaturized by integrating detection and sensing elements on the fiber. • The modular design sensor provides a detection platform for other species monitoring.

  14. Performance of solid electrolyte type oxygen sensor in flowing lead bismuth

    International Nuclear Information System (INIS)

    Kondo, Masatoshi; Takahashi, Minoru

    2005-01-01

    A solid electrolyte type oxygen sensor for liquid 45%lead-55%bismuth (Pb-Bi) was developed. The performance of the oxygen sensor in the flowing lead-bismuth (Pb-Bi) was investigated. The initial performance of the sensor was not reliable, since the reference fluid of the oxygen saturated bismuth in the sensor cell was not compact initially. The electromotive force (EMF) obtained from the yttria stabilized zirconia (YSZ) cell was the same as that from the magnesia stabilized zirconia (MSZ) cell in the flowing Pb-Bi. The EMF of the sensor in the flowing Pb-Bi was lower than that in the stagnant Pb-Bi. However, the difference was small. The sensor showed repeatability after the long term interruption and the Pb-Bi drain/charge operation. After the performance tests, the corrosion of the sensor cells were investigated metallurgically. The YSZ cell was eroded around the free surface of the flowing Pb-Bi after 3500 hour-exposure in the flowing Pb-Bi. The MSZ cell showed smooth surface without the erosion. Although the YSZ cell worked more stably than the MSZ cell, the mechanical strength of the YSZ cell is weaker than that of the MSZ cell. (author)

  15. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

    Directory of Open Access Journals (Sweden)

    Jianqiao Liu

    2017-08-01

    Full Text Available The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  16. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics.

    Science.gov (United States)

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-08-10

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  17. Singlet Oxygen Sensor Green: Photochemical Behavior in Solution and in a Mammalian Cell

    DEFF Research Database (Denmark)

    Gollmer, Anita; Arnbjerg, Jacob; Blaikie, Frances Helen

    2011-01-01

    The development of efficient and selective luminescent probes for reactive oxygen species, particularly for singlet molecular oxygen, is currently of great importance. In this study, the photochemical behavior of Singlet Oxygen Sensor Green® (SOSG), a commercially available fluorescent probe...... for singlet oxygen, was examined. Despite published claims to the contrary, the data presented herein indicate that SOSG can, in fact, be incorporated into a living mammalian cell. However, for a number of reasons, caution must be exercised when using SOSG. First, it is shown that the immediate product...... of the reaction between SOSG and singlet oxygen is, itself, an efficient singlet oxygen photosensitizer. Second, SOSG appears to efficiently bind to proteins which, in turn, can influence uptake by a cell as well as behavior in the cell. As such, incorrect use of SOSG can yield misleading data on yields...

  18. Development of oxygen sensors using zirconia solid electrolyte for fuel rods

    International Nuclear Information System (INIS)

    Hiura, Nobuo; Endou, Yasuichi; Yamaura, Takayuki; Matui, Yoshinori; Niimi, Motoji; Hoshiya, Taiji; Kobiyama, Mamoru; Motohashi, Yoshinobu

    1999-01-01

    The oxygen potential in oxide fuel pellet is an important parameter to understand behavior of high burn up fuel and its integrity. Zirconia solid electrolyte which is durable under irradiation and high temperature is considered as candidate material for the oxygen potential. Combined use of solid electrolyte and Ni/NiO as a solid standard electrode will realize small size oxygen sensor which can be easily loaded in the fuel rod. Prototypes of the oxygen sensor made of these materials were irradiated with neutrons the Japan Materials Testing Reactor (JMTR), and characteristics of electromotive force (EMF) by sensors were examined under irradiation. For a prototype using zirconia solid electrolyte stabilized by Y 2 O 3 (YSZ), measured EMF under irradiation was nearly equivalent to the value under unirradiated condition, and very stable within a range of neutron fluence (E>1 MeV) up to 1.52 x 10 23 m -2 and for the time of 600 h. However, the measured EMFs were slightly smaller than the theoretical values. The reason for this decrease of the EMF was thought as due to insufficient adhesion forces between solid electrolyte and standard electrode. After modification of the sensor to increase adhesion force, EMF was measured again under irradiation. The results showed improvement of the characteristics of the sensor in which measured EMFs were almost equivalent to the theoretical values. (author)

  19. Low-temperature behavior of ZrO2 oxygen sensors

    International Nuclear Information System (INIS)

    Badwal, S.P.S.; Bannister, M.J.

    1983-01-01

    The relative importance of the solid electrolyte and the electrodes in determining the low-temperature behavior of stabilized zirconia oxygen sensors is considered. Contrary to general belief, the electrodes play the more important role at low temperatures. The performance may be greatly improved by using, instead of porous platinum, oxide electrodes comprising solid solutions based on UO 2 . Laboratory tests and plant trials show that ideal behavior in oxygen-excess gases can be achieved below 400 0 C

  20. Enzymatic Sensor of Putrescine with Optical Oxygen Transducer - Mathematical Model of Responses of Sensitive Layer.

    Czech Academy of Sciences Publication Activity Database

    Maixnerová, Lucie; Horvitz, Alexandar; Kuncová, Gabriela; Přibyl, M.; Šebela, M.; Koštejn, Martin

    2015-01-01

    Roč. 69, č. 1 (2015), s. 158-166 ISSN 0366-6352 R&D Projects: GA TA ČR TA03010548; GA MŠk(CZ) LO1204 Institutional support: RVO:67985858 Keywords : enzymatic sensor * putrescine * optical oxygen transducer Subject RIV: CE - Biochemistry Impact factor: 1.326, year: 2015

  1. A comparison of oxygen saturation measurements obtained from a 'blue sensor' with a standard sensor.

    Science.gov (United States)

    Mawson, Isabel E; Dawson, Jennifer A; Donath, Susan M; Davis, Peter G

    2011-10-01

    The study aims to investigate pulse oximetry measurements from a 'blue' pulse oximeter sensor against measurements from a 'standard' pulse oximeter sensor in newly born infants. Immediately after birth, both sensors were attached to the infant, one to each foot. SpO₂ measurements were recorded simultaneously from each sensor for 10 min. Agreement between pairs of SpO₂ measurements were calculated using Bland-Altman analysis. Thirty-one infants were studied. There was good correlation between simultaneous SpO₂ measurements from both sensors (r² = 0.75). However, the mean difference between 'blue' and 'standard' sensors was -1.6%, with wide 95% limits of agreement +18.4 to -21.6%. The range of mean difference between sensors from each infant ranged from -20 to +20. The mean difference between the blue and standard sensor SpO₂ measurements is not clinically important. © 2011 The Authors. Journal of Paediatrics and Child Health © 2011 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  2. Fluorophore-based sensor for oxygen radicals in processing plasmas

    International Nuclear Information System (INIS)

    Choudhury, Faraz A.; Shohet, J. Leon; Sabat, Grzegorz; Sussman, Michael R.; Nishi, Yoshio

    2015-01-01

    A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye that is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye

  3. Fluorophore-based sensor for oxygen radicals in processing plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, Faraz A.; Shohet, J. Leon, E-mail: shohet@engr.wisc.edu [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Sabat, Grzegorz; Sussman, Michael R. [Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Nishi, Yoshio [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-11-15

    A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye that is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye.

  4. Neutron irradiation characteristic tests of oxygen sensors using zirconia solid electrolyte

    International Nuclear Information System (INIS)

    Hiura, Nobuo; Endou, Yasuichi; Yamaura, Takayuki; Niimi, Motoji; Hoshiya, Taiji; Saito, Junichi; Souzawa, Shizuo; Ooka, Norikazu; Kobiyama, Mamoru.

    1997-03-01

    In the Department of JMTR of Japan Atomic Energy Research Institute (JAERI), the in-situ measuring technique of oxygen potential has been being developed to study the chemical behavior of high burn-up fuel base-irradiated in the Light Water Reactor. In this test for development of the technique, oxygen sensors using zirconia solid electrolyte stabilized by MgO, CaO and Y 2 O 3 , named MSZ, CSZ and YSZ, respectively, were irradiated by neutrons in the Japan Materials Testing Reactor (JMTR) of JAERI and the characteristics of electromotive force of these sensors under and after irradiation were discussed. From the experimental results, the electromotive force of YSZ sample under irradiation decreased with an increase in irradiation fluence within a range of neutron fluence (E>1 MeV) up to 1 x 10 23 m -2 . The electromotive force of MSZ sensor irradiated with neutron fluences (E>1 MeV) up to 9 x 10 21 m -2 was almost equal to the theoretical value of the electromotive force. It was shown that after irradiation, a decrease in the electromotive force of CSZ sensor was smaller than those of MSZ and YSZ sensors, although the electromotive forces of MSZ, CSZ and YSZ sensors were smaller than the theoretical value. (author)

  5. Highly sensitive fiber-optic oxygen sensor based on palladium tetrakis (4-carboxyphenyl)porphyrin doped in ormosil

    International Nuclear Information System (INIS)

    Chu, Cheng-Shane; Chuang, Chih-Yung

    2014-01-01

    A simple, low-cost technique for fabrication of highly sensitive fiber-optic oxygen sensor is described. An organically modified silicate (ORMOSIL) as a matrix for the fabrication of oxygen sensing film was produced. The technique is based on coating the end of a plastic optical fiber with ormosil composite xerogel film sequestered with luminophore palladium (II) meso-tetra(4-carboxyphenyl)porphyrin (PdTCPP) prepared by a sol–gel process. The composite xerogel studied is tetraethylorthosilane (TEOS)/n-octyltriethoxysilane (Octyl-triEOS). Result shows that, expect for PdTCPP-doped TEOS/Octyl-triEOS composite xerogel show the high sensitivity and linear Stern–Volmer relationship which indicate the homogenous environment of the luminophore. The sensitivity of the optical oxygen sensor is quantified in terms of the ratio I N2 /I O2 , where I N2 and I O2 represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental result reveals that the PdTCPP-doped TEOS/Octyl-triEOS oxygen sensor has sensitivity of 153. - Highlights: • A simple, low-cost technique for fabrication of highly sensitive fiber-optic oxygen sensor is described. • ORMOSIL was produced to serve as a matrix for the fabrication of oxygen sensing film. • The fiber-optic oxygen sensor has sensitivity of I N2 /I 100O2 =153. • The stable and reproducible signals were obtained with the fiber-optic oxygen sensor

  6. Oxygen sensor using proton-conductor thick-film operative at room temperature. Puroton dodentai atsumaku wo mochiita joon sadogata sanso sensor

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Norio; Yoshida, Nobuaki; Matayoshi, Naoko; Shimizu, Yoichi; Yamazoe, Noboru; Kuwata, Shigeki [Kyushu Univ., Fukuoka, (Japan) Niihama National College of Tech., Ehime, (Japan)

    1989-10-01

    An amperometric solid-state oxygen sensor using a proton-conductor thick-film was examined as a miniaturized and intelligent oxygen sensor operative at room temperature. The good-conditioned proton-conductor film of about 10{mu}m in thickness without holes was formed on a porous alumina substrate by spin-coating the paste containing antimonic acid and a polyvinyl alcohol binder. Using this material, the thick-film oxygen sensor was made. A limiting current, controlled by oxygen permeation through the gas-diffusion layer, was observed when an external voltage was over 1.4V. The limiting current increased linearly with an increase in oxygen partial pressure up to 1.0 atm at an external voltage of 1.6V. The 90% response time for increasing oxygen partial pressure was about 40 seconds at 30 centigrade. Moreover, it was found that the sensor could also respond to dissolved oxygen in water at room temperature. With a sensor using a hydrophobic gas-diffusion layer containing a polystyrene binder, the limiting current was linear to the dissolved oxygen concentration up to 20ppm. 15 refs., 5 figs.

  7. Flexible Sheet-Type Sensor for Noninvasive Measurement of Cellular Oxygen Metabolism on a Culture Dish.

    Directory of Open Access Journals (Sweden)

    Mari Kojima

    Full Text Available A novel flexible sensor was developed for the noninvasive oxygen metabolism measurement of cultivated cells and tissues. This device is composed of a transparent double-layered polymer sheet of ethylene-vinyl alcohol (EVOH and poly(dimethylsiloxane (PDMS having an array of microhole structures of 90 μm diameter and 50 μm depth on its surface. All the microhole structures were equipped with a 1-μm-thick optical chemical sensing layer of platinum porphyrin-fluoropolymer on their bottom. The three-dimensional microstructures of the sensor were fabricated by a newly developed simple and low-cost production method named self-aligned hot embossing. The device was designed to be attached slightly above the cells cultivated on a dish to form a temporarily closed microspace over the target cells during measurement. Since the change in oxygen concentration is relatively fast in the microcompartmentalized culture medium, a rapid evaluation of the oxygen consumption rate is possible by measuring the phosphorescence lifetime of the platinum porphyrin-fluoropolymer. The combined use of the device and an automated optical measurement system enabled the high-throughput sensing of cellular oxygen consumption (100 points/min. We monitored the oxygen metabolism of the human breast cancer cell line MCF7 on a Petri dish and evaluated the oxygen consumption rate to be 0.72 ± 0.12 fmol/min/cell. Furthermore, to demonstrate the utility of the developed sensing system, we demonstrated the mapping of the oxygen consumption rate of rat brain slices and succeeded in visualizing a clear difference among the layer structures of the hippocampus, i.e., the cornu ammonis (CA1 and CA3 and dentate gyrus (DG.

  8. Quantifying oxygen in paper-based cell cultures with luminescent thin film sensors.

    Science.gov (United States)

    Boyce, Matthew W; Kenney, Rachael M; Truong, Andrew S; Lockett, Matthew R

    2016-04-01

    Paper-based scaffolds are an attractive material for generating 3D tissue-like cultures because paper is readily available and does not require specialized equipment to pattern, cut, or use. By controlling the exchange of fresh culture medium with the paper-based scaffolds, we can engineer diffusion-dominated environments similar to those found in spheroids or solid tumors. Oxygen tension directly regulates cellular phenotype and invasiveness through hypoxia-inducible transcription factors and also has chemotactic properties. To date, gradients of oxygen generated in the paper-based cultures have relied on cellular response-based readouts. In this work, we prepared a luminescent thin film capable of quantifying oxygen tensions in apposed cell-containing paper-based scaffolds. The oxygen sensors, which are polystyrene films containing a Pd(II) tetrakis(pentafluorophenyl)porphyrin dye, are photostable, stable in culture conditions, and not cytotoxic. They have a linear response for oxygen tensions ranging from 0 to 160 mmHg O2, and a Stern-Volmer constant (K sv) of 0.239 ± 0.003 mmHg O2 (-1). We used these oxygen-sensing films to measure the spatial and temporal changes in oxygen tension for paper-based cultures containing a breast cancer line that was engineered to constitutively express a fluorescent protein. By acquiring images of the oxygen-sensing film and the fluorescently labeled cells, we were able to approximate the oxygen consumption rates of the cells in our cultures.

  9. Oxygen sensor via the quenching of room-temperature phosphorescence of perdeuterated phenanthrene adsorbed on Whatman 1PS filter paper.

    Science.gov (United States)

    Ramasamy, S M; Hurtubise, R J

    1998-11-01

    Perdeuterated phenanthrene (d-phen) exhibits strong room-temperature phosphorescence (RTP) when adsorbed on Whatman 1PS filter paper. An oxygen sensor was developed that depends on oxygen quenching of RTP intensity of adsorbed d-phen. The system designed employed a continuous flow of nitrogen or nitrogen-air onto the adsorbed phosphor. The sensor is simple to prepare and needs no elaborate fabrication procedure, but did show a somewhat drifting baseline for successive determinations of oxygen. Nevertheless, very good reproducibility was achieved with the RTP quenching data by measuring the RTP intensities just before and at the end of each oxygen determination. The calibration plots gave a nonlinear relationship over the entire range of oxygen (0-21%). However, a linear range was obtained up to 1.10% oxygen. A detection limit of 0.09% oxygen in dry nitrogen was acquired. Also, carbon dioxide was found to have a minimal effect on the RTP quenching. Thus, oxygen could be measured accurately in relatively large amounts of carbon dioxide. The performance of the oxygen sensor was evaluated by comparing data obtained with a commercial electrochemical trace oxygen analyzer. Also, additional information on the quenching phenomena for this system was obtained from the RTP lifetime data acquired at various oxygen contents.

  10. Steady-state modelling of the universal exhaust gas oxygen (UEGO) sensor

    International Nuclear Information System (INIS)

    Collings, N; Hegarty, K; Ramsander, T

    2012-01-01

    The universal exhaust gas oxygen (UEGO) sensor is a well-established device which was developed for the measurement of relative air fuel ratio in internal combustion engines. There is, however, little information available which allows for the prediction of the UEGO's behaviour when exposed to arbitrary gas mixtures, pressures and temperatures. Here we present a steady-state model for the sensor, based on a solution of the Stefan–Maxwell equation, and which includes a momentum balance. The response of the sensor is dominated by a diffusion barrier, which controls the rate of diffusion of gas species between the exhaust and a cavity. Determination of the diffusion barrier characteristics, especially the mean pore size, porosity and tortuosity, is essential for the purposes of modelling, and a measurement technique based on identification of the sensor pressure giving zero temperature sensitivity is shown to be a convenient method of achieving this. The model, suitably calibrated, is shown to make good predictions of sensor behaviour for large variations of pressure, temperature and gas composition. (paper)

  11. Performance Evaluation of an Oxygen Sensor as a Function of the Samaria Doped Ceria Film Thickness

    International Nuclear Information System (INIS)

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Jiang, Weilin; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

    2010-01-01

    The current demand in the automobile industry is in the control of air-fuel mixture in the combustion engine of automobiles. Oxygen partial pressure can be used as an input parameter for regulating or controlling systems in order to optimize the combustion process. Our goal is to identify and optimize the material system that would potentially function as the active sensing material for such a device that monitors oxygen partial pressure in these systems. We have used thin film samaria doped ceria (SDC) as the sensing material for the sensor operation, exploiting the fact that at high temperatures, oxygen vacancies generated due to samarium doping act as conducting medium for oxygen ions which hop through the vacancies from one side to the other contributing to an electrical signal. We have recently established that 6 atom% Sm doping in ceria films has optimum conductivity. Based on this observation, we have studied the variation in the overall conductivity of 6 atom% samaria doped ceria thin films as a function of thickness in the range of 50 nm to 300 nm at a fixed bias voltage of 2 volts. A direct proportionality in the increase in the overall conductivity is observed with the increase in sensing film thickness. For a range of oxygen pressure values from 1 mTorr to 100 Torr, a tolerable hysteresis error, good dynamic response and a response time of less than 10 seconds was observed

  12. Integrated oxygen sensors based on Mg-doped SrTiO3 fabricated by screen-printing

    DEFF Research Database (Denmark)

    Zheng, H.; Toft Sørensen, O.

    1998-01-01

    This paper describes the fabrication and testing of Mg-doped SrTiO3 thick-film oxygen sensors with an integrated Pt heater. The results show that the sensor exhibits a PO2 dependence according to R proportional to PO2-1/4 in the considered PO2 range(2.5 x 10(-5) bar

  13. Development of oxygen and pH sensors for aqueous systems

    International Nuclear Information System (INIS)

    Stvartak, C.; Alcock, C.B.; Li, B.; Wang, L.; Fergus, J.W.; Bakshi, N.

    1994-04-01

    Corrosion science has long recognized that two of the most important parameters in characterizing the corrosivity of an aqueous environment are oxygen chemical potential and pH. These parameters not only determine the thermodynamic driving forces for various corrosion reactions, but also characterize the rates of these reactions and hence the lifetime of a particular component. The primary goal of this project is to develop an electrochemical oxygen and pH sensor for continuous use in the cycle chemistry control of power plants. In the past year, electrochemical sensors with a metal/metal oxide or metal/metal hydride internal reference electrode and a fluoride-based electrolyte tube have been developed and tested in this laboratory. The corrosion tests showed that the LaF 3 -based solid electrolyte was very stable both chemically and physically in water. Furthermore, its electrical conductivity is 4 to 5 orders of magnitude higher than that of stabilized zirconia below 573 K (300 degree C), which is the main advantage of a fluoride-based electrolyte at low temperatures. With this electrolyte and the selected internal oxygen reference electrode (Ag/Ag 2 O), the electrochemical probe demonstrated Nernstian responses to the oxygen chemical potential and pH of the aqueous solution with good reproducibility. A similar cell with Zr/ZrH 1+x as the internal hydrogen reference electrode showed promising pH sensing characteristics. It is proposed that these two cells be combined to form a double-headed electrochemical probe to determine oxygen chemical potential and pH in the solution simultaneously

  14. An optode sensor array for long term in situ Oxygen measurements in soil and sediment

    DEFF Research Database (Denmark)

    Rickelt, Lars F; Jensen, Louise Askær; Walpersdorf, Eva Christine

    2013-01-01

    Long-term measurements of molecular oxygen (O2) dynamics in wetlands are highly relevant for understanding the eff ects of water level changes on net greenhouse gas budgets in these ecosystems. However, such measurements have been limited due to a lack of suitable measuring equipment. We construc......Long-term measurements of molecular oxygen (O2) dynamics in wetlands are highly relevant for understanding the eff ects of water level changes on net greenhouse gas budgets in these ecosystems. However, such measurements have been limited due to a lack of suitable measuring equipment. We...... constructed an O2 optode sensor array for long-term in situ measurements in soil and sediment. Th e new device consists of a 1.3-m-long, cylindrical, spear-shaped rod equipped with 10 sensor spots along the shaft . Each spot contains a thermocouple fi xed with a robust fi beroptic O2 optode made...... characteristics of the sensor array system are presented along with a novel approach for temperature compensation of O2 optodes. During in situ application over several months in a peat bog, we used the new device to document pronounced variations in O2 distribution aft er marked shift s in water level. Th e...

  15. Microfabricated Collector-Generator Electrode Sensor for Measuring Absolute pH and Oxygen Concentrations.

    Science.gov (United States)

    Dengler, Adam K; Wightman, R Mark; McCarty, Gregory S

    2015-10-20

    Fast-scan cyclic voltammetry (FSCV) has attracted attention for studying in vivo neurotransmission due to its subsecond temporal resolution, selectivity, and sensitivity. Traditional FSCV measurements use background subtraction to isolate changes in the local electrochemical environment, providing detailed information on fluctuations in the concentration of electroactive species. This background subtraction removes information about constant or slowly changing concentrations. However, determination of background concentrations is still important for understanding functioning brain tissue. For example, neural activity is known to consume oxygen and produce carbon dioxide which affects local levels of oxygen and pH. Here, we present a microfabricated microelectrode array which uses FSCV to detect the absolute levels of oxygen and pH in vitro. The sensor is a collector-generator electrode array with carbon microelectrodes spaced 5 μm apart. In this work, a periodic potential step is applied at the generator producing transient local changes in the electrochemical environment. The collector electrode continuously performs FSCV enabling these induced changes in concentration to be recorded with the sensitivity and selectivity of FSCV. A negative potential step applied at the generator produces a transient local pH shift at the collector. The generator-induced pH signal is detected using FSCV at the collector and correlated to absolute solution pH by postcalibration of the anodic peak position. In addition, in oxygenated solutions a negative potential step at the generator produces hydrogen peroxide by reducing oxygen. Hydrogen peroxide is detected with FSCV at the collector electrode, and the magnitude of the oxidative peak is proportional to absolute oxygen concentrations. Oxygen interference on the pH signal is minimal and can be accounted for with a postcalibration.

  16. Net community production at Ocean Station Papa observed with nitrate and oxygen sensors on profiling floats

    Science.gov (United States)

    Plant, Joshua N.; Johnson, Kenneth S.; Sakamoto, Carole M.; Jannasch, Hans W.; Coletti, Luke J.; Riser, Stephen C.; Swift, Dana D.

    2016-06-01

    Six profiling floats equipped with nitrate and oxygen sensors were deployed at Ocean Station P in the Gulf of Alaska. The resulting six calendar years and 10 float years of nitrate and oxygen data were used to determine an average annual cycle for net community production (NCP) in the top 35 m of the water column. NCP became positive in February as soon as the mixing activity in the surface layer began to weaken, but nearly 3 months before the traditionally defined mixed layer began to shoal from its winter time maximum. NCP displayed two maxima, one toward the end of May and another in August with a summertime minimum in June corresponding to the historical peak in mesozooplankton biomass. The average annual NCP was determined to be 1.5 ± 0.6 mol C m-2 yr-1 using nitrate and 1.5 ± 0.7 mol C m-2 yr-1 using oxygen. The results from oxygen data proved to be quite sensitive to the gas exchange model used as well as the accuracy of the oxygen measurement. Gas exchange models optimized for carbon dioxide flux generally ignore transport due to gas exchange through the injection of bubbles, and these models yield NCP values that are two to three time higher than the nitrate-based estimates. If nitrate and oxygen NCP rates are assumed to be related by the Redfield model, we show that the oxygen gas exchange model can be optimized by tuning the exchange terms to reproduce the nitrate NCP annual cycle.

  17. Engineering glucose oxidase to minimize the influence of oxygen on sensor response

    International Nuclear Information System (INIS)

    Horaguchi, Yohei; Saito, Shoko; Kojima, Katsuhiro; Tsugawa, Wakako; Ferri, Stefano; Sode, Koji

    2014-01-01

    Glucose oxidase (GOx) is an important industrial enzyme and is recognized as the gold standard for monitoring blood glucose. However, due to its inherent oxidase property, the presence of oxygen affects electrochemical measurements of venous blood glucose employing artificial electron mediators. We therefore attempted to engineer Penicillium amagasakiense-derived GOx into a dehydrogenase by focusing on the amino acid residues predicted to interact with oxygen. Our rational amino acid substitution approach resulted in the construction of the Ser114Ala/Phe355Leu mutant, which has an 11-fold decrease in oxidase activity and 2.8-fold increase in dehydrogenase activity compared with wild-type GOx. As a result, the dehydrogenase/oxidase activity ratio of the engineered enzyme was 32-fold greater than that of the wild-type enzyme. The enzyme sensor constructed with Ser114Ala/Phe355Leu was considerably less affected by oxygen than the wild-type GOx-based sensor at lower glucose concentrations

  18. Methods and Best Practice to Intercompare Dissolved Oxygen Sensors and Fluorometers/Turbidimeters for Oceanographic Applications

    Directory of Open Access Journals (Sweden)

    Sara Pensieri

    2016-05-01

    Full Text Available In European seas, ocean monitoring strategies in terms of key parameters, space and time scale vary widely for a range of technical and economic reasons. Nonetheless, the growing interest in the ocean interior promotes the investigation of processes such as oxygen consumption, primary productivity and ocean acidity requiring that close attention is paid to the instruments in terms of measurement setup, configuration, calibration, maintenance procedures and quality assessment. To this aim, two separate hardware and software tools were developed in order to test and simultaneously intercompare several oxygen probes and fluorometers/turbidimeters, respectively in the same environmental conditions, with a configuration as close as possible to real in-situ deployment. The chamber designed to perform chlorophyll-a and turbidity tests allowed for the simultaneous acquisition of analogue and digital signals of several sensors at the same time, so it was sufficiently compact to be used in both laboratory and onboard vessels. Methodologies and best practice committed to the intercomparison of dissolved oxygen sensors and fluorometers/turbidimeters have been used, which aid in the promotion of interoperability to access key infrastructures, such as ocean observatories and calibration facilities. Results from laboratory tests as well as field tests in the Mediterranean Sea are presented.

  19. Composite Sr- and V-doped LaCrO3/YSZ sensor electrode operating at low oxygen levels

    DEFF Research Database (Denmark)

    Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels

    2012-01-01

    A porous composite electrode of La0.8Sr0.2Cr0.97V0.03O3 -delta (LSCV) and yttria-stabilised zirconia (YSZ) was evaluated as a possible candidate for high-temperature potentiometric oxygen sensor measuring electrodes. The oxygen processes at the electrode were characterised by performing electroch....... The relatively low response time at 700º C at an oxygen partial pressure of around 5x10-6 bar and an inlet gas flow rate of 8 L h-1 makes the LSCV/YSZ electrode suitable for use as an potentiometric oxygen sensor electrodes.......A porous composite electrode of La0.8Sr0.2Cr0.97V0.03O3 -delta (LSCV) and yttria-stabilised zirconia (YSZ) was evaluated as a possible candidate for high-temperature potentiometric oxygen sensor measuring electrodes. The oxygen processes at the electrode were characterised by performing...... and 400 nm. At oxygen partial pressures around 0.2 bar at 700º C, the oxygen reaction is dominated by solid-state diffusion of oxide ions and surface reaction kinetics. At oxygen partial pressures around 10-5 bar above 800º C, gas phase mass transport processes dominate the impedance spectra...

  20. A laser-based sensor for measurement of off-gas composition and temperature in basic oxygen steelmaking

    International Nuclear Information System (INIS)

    Ottesen, D.; Allendorf, S.; Ludowise, P.; Hardesty, D.; Miller, T.; Goldstein, D.; Smith, C.; Bonin, M.

    1999-01-01

    We are developing an optical sensor for process control in basic oxygen steelmaking. The sensor measures gas temperature and relative CO/CO 2 concentration ratios in the furnace off-gas by transmitting the laser probe beam directly above the furnace lip and below the exhaust hood during oxygen blowing. Dynamic off-gas information is being evaluated for optimizing variables such as lance height, oxygen flow, post-combustion control, and prediction of final melt-carbon content. The non-invasive nature of the optical sensor renders it robust and relatively maintenance-free. Additional potential applications of the method are process control for electric arc furnace and bottom-blown oxygen steelmaking processes. (author)

  1. Nanostructured oxygen sensor--using micelles to incorporate a hydrophobic platinum porphyrin.

    Directory of Open Access Journals (Sweden)

    Fengyu Su

    Full Text Available Hydrophobic platinum(II-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl-porphyrin (PtTFPP was physically incorporated into micelles formed from poly(ε-caprolactone-block-poly(ethylene glycol to enable the application of PtTFPP in aqueous solution. Micelles were characterized using dynamic light scattering (DLS and atomic force microscopy (AFM to show an average diameter of about 140 nm. PtTFPP showed higher quantum efficiency in micellar solution than in tetrahydrofuran (THF and dichloromethane (CH₂Cl₂. PtTFPP in micelles also exhibited higher photostability than that of PtTFPP suspended in water. PtTFPP in micelles exhibited good oxygen sensitivity and response time. This study provided an efficient approach to enable the application of hydrophobic oxygen sensors in a biological environment.

  2. Microbial nar-GFP cell sensors reveal oxygen limitations in highly agitated and aerated laboratory-scale fermentors

    Directory of Open Access Journals (Sweden)

    Rao Govind

    2009-01-01

    Full Text Available Abstract Background Small-scale microbial fermentations are often assumed to be homogeneous, and oxygen limitation due to inadequate micromixing is often overlooked as a potential problem. To assess the relative degree of micromixing, and hence propensity for oxygen limitation, a new cellular oxygen sensor has been developed. The oxygen responsive E. coli nitrate reductase (nar promoter was used to construct an oxygen reporter plasmid (pNar-GFPuv which allows cell-based reporting of oxygen limitation. Because there are greater than 109 cells in a fermentor, one can outfit a vessel with more than 109 sensors. Our concept was tested in high density, lab-scale (5 L, fed-batch, E. coli fermentations operated with varied mixing efficiency – one verses four impellers. Results In both cases, bioreactors were maintained identically at greater than 80% dissolved oxygen (DO during batch phase and at approximately 20% DO during fed-batch phase. Trends for glucose consumption, biomass and DO showed nearly identical behavior. However, fermentations with only one impeller showed significantly higher GFPuv expression than those with four, indicating a higher degree of fluid segregation sufficient for cellular oxygen deprivation. As the characteristic time for GFPuv expression (approx 90 min. is much larger than that for mixing (approx 10 s, increased specific fluorescence represents an averaged effect of oxygen limitation over time and by natural extension, over space. Conclusion Thus, the pNar-GFPuv plasmid enabled bioreactor-wide oxygen sensing in that bacterial cells served as individual recirculating sensors integrating their responses over space and time. We envision cell-based oxygen sensors may find utility in a wide variety of bioprocessing applications.

  3. Low cost chemical oxygen demand sensor based on electrodeposited nano-copper film

    Directory of Open Access Journals (Sweden)

    Hamdy H. Hassan

    2018-02-01

    Full Text Available A commercially available copper electrical cable and pure Cu disk were used as substrates for the electrodeposition of copper nanoparticles (nano-Cu. The surface morphology of the prepared nano-Cu/Cu electrodes was investigated by scanning electron microscope (SEM and energy dispersive X-ray spectrometer (EDX. The bare copper substrates and the nano-copper modified electrodes were utilized and optimized for electrochemical assay of chemical oxygen demand (COD using glycine as a standard. A comparison was made among the four electrodes (i.e., bare and nano-Cu coated copper cable and pure copper disk as potential COD sensors. The oxidation behavior of glycine was investigated on the surface of the prepared sensors using linear sweep voltammetry (LSV. The results indicate significant enhancement of the electrochemical oxidation of glycine by the deposited nano-Cu. The effects of different deposition parameters, such as Cu2+ concentration, deposition potential, deposition time, pH, and scan rate on the response of the prepared sensors were investigated. Under optimized conditions, the optimal nano-Cu based COD sensor exhibited a linear range of 2–595 mg/L, lower limit of detection (LOD as low as 1.07 mg/L (S/N = 3. The developed method exhibited high tolerance level to Cl− ion where 1.0 M Cl− exhibited minimal influence. The sensor was utilized for the detection of COD in different real water samples. The results obtained were validated using the standard dichromate method.

  4. Optical monitoring of kidney oxygenation and hemodynamics using a miniaturized near-infrared sensor

    Science.gov (United States)

    Shadgan, Babak; Macnab, Andrew; Nigro, Mark; Nguan, Christopher

    2017-02-01

    Background: Following human renal allograft transplant primary graft dysfunction can occur early in the postoperative period as a result of acute tubular necrosis, acute rejection, drug toxicity, and vascular complications. Successful treatment of graft dysfunction requires early detection and accurate diagnosis so that disease-specific medical and/or surgical intervention can be provided promptly. However, current diagnostic methods are not sensitive or specific enough, so that identifying the cause of graft dysfunction is problematic and often delayed. Near-infrared spectroscopy (NIRS) is an established optical method that monitors changes in tissue hemodynamics and oxygenation in real time. We report the feasibility of directly monitoring kidney the kidney in an animal model using NIRS to detect renal ischemia and hypoxia. Methods: In an anesthetized pig, a customized continuous wave spatially resolved (SR) NIRS sensor was fixed directly to the surface of the surgically exposed kidney. Changes in the concentration of oxygenated (O2Hb) deoxygenated (HHb) and total hemoglobin (THb) were monitored before, during and after renal artery clamping and reperfusion, and the resulting fluctuations in chromophore concentration from baseline used to measure variations in renal perfusion and oxygenation. Results: On clamping the renal artery THb and O2Hb concentrations declined progressively while HHb rose. With reperfusion after releasing the artery clamp O2Hb and THb rose while HHb fell with all parameters returning to its baseline. This pattern was similar in all three trials. Conclusion: This pilot study indicates that a miniaturized NIRS sensor applied directly to the surface of a kidney in an animal model can detect the onset of renal ischemia and tissue hypoxia. With modification, our NIRS-based method may contribute to early detection of renal vascular complications and graft dysfunction following renal transplant.

  5. Study on the inside gas flow visualization of oxygen sensor cover; Kashika ni yoru O2 sensor cover nai no gas nagare hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Hocho, S; Mitsuishi, Y; Inagaki, M [Nippon Soken, Inc., Tokyo (Japan); Hamaguchi, S; Mizusawa, K [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    In order to make clear the difference of the response time between the oxygen sensors with different protection covers, we visualized gas flow inside of sensor covers by means of two experimental methods: One is `Smoke Suspension Method` using liquid paraffin vapor as the smoke. With smoke suspension method, we detected the streamlines inside of the covers. The other is `Color Reaction Method` using the reaction of phenolphthalein and NH3 gas. With color reaction method, we confirmed the streamline inside of the cover and furthermore detected the difference of the response time of each sensor. 3 refs., 7 figs., 1 tab.

  6. Elaboration and characterization of solid electrolytes for electrochemical oxygen sensors in liquid sodium

    International Nuclear Information System (INIS)

    Gabard, M.

    2013-01-01

    This PhD thesis was prepared within the framework of the research program on 'Generation IV' nuclear reactors with sodium as coolant. One of the main technological problem concerns the control of the corrosion processes of the materials (structural materials, fuel claddings, etc.) by liquid sodium. A key parameter is the dissolved oxygen content in the coolant. This thesis focuses on the development and characterization of ceramic materials based on ThO 2 doped with Y 2 O 3 for making potentiometric oxygen sensor used in liquid sodium. Work has been carried out and probes were tested in the past, however, the probes had at the time, a lack of reliability. The objective of this thesis is to develop and characterize electrolytes based on thorium oxide doped with yttrium oxide using specific synthesis techniques to control purity, grain size, compactness, etc. To develop experimental protocols a ceramic model has been chosen, i.e., yttria-doped ceria. Transport processes were studied using the impedance spectroscopy technique. An interpretation of the blocking phenomena of the ionic conduction in both ceramics as a function of the oxygen partial pressure has been given. (author) [fr

  7. Subpicosecond oxygen trapping in the heme pocket of the oxygen sensor FixL observed by time-resolved resonance Raman spectroscopy.

    Science.gov (United States)

    Kruglik, Sergei G; Jasaitis, Audrius; Hola, Klara; Yamashita, Taku; Liebl, Ursula; Martin, Jean-Louis; Vos, Marten H

    2007-05-01

    Dissociation of oxygen from the heme domain of the bacterial oxygen sensor protein FixL constitutes the first step in hypoxia-induced signaling. In the present study, the photodissociation of the heme-O2 bond was used to synchronize this event, and time-resolved resonance Raman (TR(3)) spectroscopy with subpicosecond time resolution was implemented to characterize the heme configuration of the primary photoproduct. TR(3) measurements on heme-oxycomplexes are highly challenging and have not yet been reported. Whereas in all other known six-coordinated heme protein complexes with diatomic ligands, including the oxymyoglobin reported here, heme iron out-of-plane motion (doming) occurs faster than 1 ps after iron-ligand bond breaking; surprisingly, no sizeable doming is observed in the oxycomplex of the Bradyrhizobium japonicum FixL sensor domain (FixLH). This assessment is deduced from the absence of the iron-histidine band around 217 cm(-1) as early as 0.5 ps. We suggest that efficient ultrafast oxygen rebinding to the heme occurs on the femtosecond time scale, thus hindering heme doming. Comparing WT oxy-FixLH, mutant proteins FixLH-R220H and FixLH-R220Q, the respective carbonmonoxy-complexes, and oxymyoglobin, we show that a hydrogen bond of the terminal oxygen atom with the residue in position 220 is responsible for the observed behavior; in WT FixL this residue is arginine, crucially implicated in signal transmission. We propose that the rigid O2 configuration imposed by this residue, in combination with the hydrophobic and constrained properties of the distal cavity, keep dissociated oxygen in place. These results uncover the origin of the "oxygen cage" properties of this oxygen sensor protein.

  8. Integrated oxygen sensors based on Mg-doped SrTiO3 fabricated by screen-printing

    DEFF Research Database (Denmark)

    Zheng, H.; Sørensen, Ole Toft

    2000-01-01

    This paper describes the fabrication and testing of Mg-doped SrTiO3 thick-film oxygen sensors with an integrated Pt heater. The results show that the sensor exhibits a P-o2 dependence according to R proportional to p(o2)(-1/4) in the considered P-o2 range(2.5 x 10(-5) bar

  9. A flowing liquid test system for assessing the linearity and time-response of rapid fibre optic oxygen partial pressure sensors.

    Science.gov (United States)

    Chen, R; Hahn, C E W; Farmery, A D

    2012-08-15

    The development of a methodology for testing the time response, linearity and performance characteristics of ultra fast fibre optic oxygen sensors in the liquid phase is presented. Two standard medical paediatric oxygenators are arranged to provide two independent extracorporeal circuits. Flow from either circuit can be diverted over the sensor under test by means of a system of rapid cross-over solenoid valves exposing the sensor to an abrupt change in oxygen partial pressure, P O2. The system is also capable of testing the oxygen sensor responses to changes in temperature, carbon dioxide partial pressure P CO2 and pH in situ. Results are presented for a miniature fibre optic oxygen sensor constructed in-house with a response time ≈ 50 ms and a commercial fibre optic sensor (Ocean Optics Foxy), when tested in flowing saline and stored blood. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Mature Erythrocytes of Iguana iguana (Squamata, Iguanidae Possess Functional Mitochondria.

    Directory of Open Access Journals (Sweden)

    Giuseppina Di Giacomo

    Full Text Available Electron microscopy analyses of Iguana iguana blood preparations revealed the presence of mitochondria within erythrocytes with well-structured cristae. Fluorescence microscopy analyses upon incubation with phalloidin-FITC, Hoechst 33342 and mitochondrial transmembrane potential (Δψm-sensitive probe MitoTracker Red indicated that mitochondria i widely occur in erythrocytes, ii are polarized, and iii seem to be preferentially confined at a "perinuclear" region, as confirmed by electron microscopy. The analysis of NADH-dependent oxygen consumption showed that red blood cells retain the capability to consume oxygen, thereby providing compelling evidence that mitochondria of Iguana erythrocytes are functional and capable to perform oxidative phosphorylation.

  11. Mature Erythrocytes of Iguana iguana (Squamata, Iguanidae) Possess Functional Mitochondria.

    Science.gov (United States)

    Di Giacomo, Giuseppina; Campello, Silvia; Corrado, Mauro; Di Giambattista, Livia; Cirotti, Claudia; Filomeni, Giuseppe; Gentile, Gabriele

    2015-01-01

    Electron microscopy analyses of Iguana iguana blood preparations revealed the presence of mitochondria within erythrocytes with well-structured cristae. Fluorescence microscopy analyses upon incubation with phalloidin-FITC, Hoechst 33342 and mitochondrial transmembrane potential (Δψm)-sensitive probe MitoTracker Red indicated that mitochondria i) widely occur in erythrocytes, ii) are polarized, and iii) seem to be preferentially confined at a "perinuclear" region, as confirmed by electron microscopy. The analysis of NADH-dependent oxygen consumption showed that red blood cells retain the capability to consume oxygen, thereby providing compelling evidence that mitochondria of Iguana erythrocytes are functional and capable to perform oxidative phosphorylation.

  12. First experience with a novel luminescence-based optical sensor for measurement of oxygenation in tumors

    International Nuclear Information System (INIS)

    Jarm, T.; Miklavcic, D.; Lesnicar, H.; Sersa, G.

    2001-01-01

    Background. The purpose of this preliminary study was to evaluate a novel luminescence-based fiber-optic sensor (OxyLite system) for the measurement of partial pressure of oxygen (pO 2 ) in tumors and for the detection of changes in pO 2 as a function of time. The new method was used simultaneously with the laser Doppler flowmetry method for the measurement of relative tissue perfusion. Materials and methods. Blood perfusion and pO 2 were measured continuously via fiber-optic sensors inserted into SA-1 tumors in anesthetized A/J mice. The changes in blood flow and oxygenation of tumors were induced by transient changes of the parameters of anesthesia and by injection of a vasoactive drug hydralazine. Results. Both optical methods used in the study successfully detected the induced changes in blood flow and pO 2 . The measurements of pO 2 were well correlated with measurements of microcirculatory blood perfusion. In the majority of pO 2 measurements, we observed an unexpected behavior of the signal during the stabilization process immediately after the insertion of the probe into tumor. This behaviour of the pO 2 signal was most probably caused by local tissue damage induced by the insertion of the probe. Conclusion. The novel luminescence-based optical oximetry can reliably detect local pO 2 changes in tumors as a function of time but some aspects of prolonged pO 2 measurement by this method require further investigation. (author)

  13. THE DEVELOPMENT OF BIOCHEMICAL OXYGEN DEMAND SENSOR USING LOCAL YEAST: Candida fukuyamaensis, UICC Y-247

    Directory of Open Access Journals (Sweden)

    Endang Saepudin

    2011-04-01

    Full Text Available In order to shorten the measurement time of biochemical oxygen demand (BOD, a BOD sensor based on yeastmetabolism was developed. Local yeast, Indonesian Origin, Candida fukuyamaensis UICC Y-247, was used as atransducer. The yeast was immobilized as a thin film in agarose matrix with the auxiliary of Nafion® acting as themembrane for ion exchange process. The film was then attached to gold-modified glassy carbons and used as transduceron the working electrodes. The measurements were conducted by observing the depletion of glucose concentrationusing multipulse amperometric method and then converted to BOD values. Optimum condition was observed in awaiting measurement time of 30 min at an applied potential of 450 mV (vs. Ag/AgCl. Linearity was shown in glucoseconcentration range of 0.1–0.5 mM, which was equivalent to BOD concentration range of 10–50 mg/L. A detectionlimit of 1.13 mg/L BOD could be achieved. Good repeatability was shown by a relative standard deviation (RSD of2.7% (n = 15. However, decreasing current response of ~50% was found after 3 days. Comparing to the conventionalBOD measurement, this BOD sensor can be used as an alternative method for BOD measurements.

  14. Phosphorus doped TiO2 as oxygen sensor with low operating temperature and sensing mechanism

    International Nuclear Information System (INIS)

    Han, Zhizhong; Wang, Jiejie; Liao, Lan; Pan, Haibo; Shen, Shuifa; Chen, Jianzhong

    2013-01-01

    Nano-scale TiO 2 powders doped with phosphorus were prepared by sol–gel method. The characterization of the materials was performed by XRD, BET, FT-IR spectroscopy, Zeta potential measurement and XPS analysis. The results indicate that the phosphorus suppresses the crystal growth and phase transformation and, at the same time, increases the surface area and enhances the sensitivity and selectivity for the P-doped TiO 2 oxygen sensors. In this system, the operating temperature is low, only 116 °C, and the response time is short. The spectra of FT-IR and XPS show that the phosphorus dopant presents as the pentavalent-oxidation state in TiO 2 , further phosphorus can connect with Ti 4+ through the bond of Ti-O-P. The positive shifts of XPS peaks indicate that electron depleted layer of P-doped TiO 2 is narrowed compared with that of pure TiO 2 , and the results of Zeta potential illuminate that the density of surface charge carrier is intensified. The adsorptive active site and Lewis acid characteristics of the surface are reinforced by phosphorus doping, where phosphorus ions act as a new active site. Thus, the sensitivity of P-doped TiO 2 is improved, and the 5 mol% P-doped sample has the optimal oxygen sensing properties.

  15. Nanosized TiO[subscript 2] for Photocatalytic Water Splitting Studied by Oxygen Sensor and Data Logger

    Science.gov (United States)

    Zhang, Ruinan; Liu, Song; Yuan, Hongyan; Xiao, Dan; Choi, Martin M. F.

    2012-01-01

    Photocatalytic water splitting by semiconductor photocatalysts has attracted considerable attention in the past few decades. In this experiment, nanosized titanium dioxide (nano-TiO[subscript 2]) particles are used to photocatalytically split water, which is then monitored by an oxygen sensor. Sacrificial reagents such as organics (EDTA) and metal…

  16. Using micro-patterned sensors and cell self-assembly for measuring the oxygen consumption rate of single cells

    International Nuclear Information System (INIS)

    Etzkorn, James R; Parviz, Babak A; Wu, Wen-Chung; Tian, Zhiyuan; Kim, Prince; Jang, Sei-Hum; Jen, Alex K-Y; Meldrum, Deirdre R

    2010-01-01

    We present a method for self-assembling arrays of live single cells on a glass chip using a photopatternable polymer to form micro-traps. We have studied the single-cell self-assembly method and optimized the process to obtain a 52% yield of single-trapped cells. We also report a method to measure the oxygen consumption rate of a single cell using micro-patterned sensors. These molecular oxygen sensors were fabricated around each micro-trap allowing optical interrogation of oxygen concentration in the immediate environment of the trapped cell. Micromachined micro-wells were then used to seal the trap, sensor and cell in order to determine the oxygen consumption rate of single cells. These techniques reported here add to the collection of tools for performing 'singe-cell' biology. An oxygen consumption rate of 1.05 ± 0.28 fmol min −1 was found for a data set consisting of 25 single A549 cells.

  17. Hydrogen generation monitoring and mass gain analysis during the steam oxidation for Zircaloy using hydrogen and oxygen sensors

    International Nuclear Information System (INIS)

    Fukumoto, Michihisa; Hara, Motoi; Kaneko, Hiroyuki; Sakuraba, Takuya

    2015-01-01

    The oxidation behavior of Zircaloy-4 at high temperatures in a flowing Ar-H_2O (saturated at 323 K) mixed gas was investigated using hydrogen and oxygen sensors installed at a gas outlet, and the utility of the gas sensing methods by using both sensors was examined. The generated amount of hydrogen was determined from the hydrogen partial pressure continuously measured by the hydrogen sensor, and the resultant calculated oxygen amount that reacted with the specimen was in close agreement with the mass gain gravimetrically measured after the experiment. This result demonstrated that the hydrogen partial pressure measurement using a hydrogen sensor is an effective method for examining the steam oxidation of this metal as well as monitoring the hydrogen evolution. The advantage of this method is that the oxidation rate of the metal at any time as a differential quantity is able to be obtained, compared to the oxygen amount gravimetrically measured as an integral quantity. When the temperature was periodically changed in the range of 1173 K to 1523 K, highly accurate measurements could be carried out using this gas monitoring method, although reasonable measurements were not gravimetrically performed due to the fluctuating thermo-buoyancy during the experiment. A change of the oxidation rate was clearly detected at a monoclinic tetragonal transition temperature of ZrO_2. From the calculation of the water vapor partial pressure during the thermal equilibrium condition using the hydrogen and oxygen partial pressures, it became clear that a thermal equilibrium state is maintained when the isothermal condition is maintained, but is not when the temperature increases or decreases with time. Based on these results, it was demonstrated that the gas monitoring system using hydrogen and oxygen sensors is very useful for investigating the oxidation process of the Zircaloy in steam. (author)

  18. Electron Pathways through Erythrocyte Plasma Membrane in Human Physiology and Pathology: Potential Redox Biomarker?

    OpenAIRE

    Matteucci, Elena; Giampietro, Ottavio

    2007-01-01

    Erythrocytes are involved in the transport of oxygen and carbon dioxide in the body. Since pH is the influential factor in the Bohr-Haldane effect, pHi is actively maintained via secondary active transports Na+/H+ exchange and HC3 -/Cl- anion exchanger. Because of the redox properties of the iron, hemoglobin generates reactive oxygen species and thus, the human erythrocyte is constantly exposed to oxidative damage. Although the adult erythrocyte lacks protein synthesis and cannot restore dama...

  19. Oxygen partial pressure effects on the RF sputtered p-type NiO hydrogen gas sensors

    Science.gov (United States)

    Turgut, Erdal; Çoban, Ömer; Sarıtaş, Sevda; Tüzemen, Sebahattin; Yıldırım, Muhammet; Gür, Emre

    2018-03-01

    NiO thin films were grown by Radio Frequency (RF) Magnetron Sputtering method under different oxygen partial pressures, which are 0.6 mTorr, 1.3 mTorr and 2.0 mTorr. The effects of oxygen partial pressures on the thin films were analyzed through Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Hall measurements. The change in the surface morphology of the thin films has been observed with the SEM and AFM measurements. While nano-pyramids have been obtained on the thin film grown at the lowest oxygen partial pressure, the spherical granules lower than 60 nm in size has been observed for the samples grown at higher oxygen partial pressures. The shift in the dominant XRD peak is realized to the lower two theta angle with increasing the oxygen partial pressures. XPS measurements showed that the Ni2p peak involves satellite peaks and two oxidation states of Ni, Ni2+ and Ni3+, have been existed together with the corresponding splitting in O1s spectrum. P-type conductivity of the grown NiO thin films are confirmed by the Hall measurements with concentrations on the order of 1013 holes/cm-3. Gas sensor measurements revealed minimum of 10% response to the 10 ppm H2 level. Enhanced responsivity of the gas sensor devices of NiO thin films is shown as the oxygen partial pressure increases.

  20. New hybrid reflectance optical pulse oximetry sensor for lower oxygen saturation measurement and for broader clinical application

    Science.gov (United States)

    Nogawa, Masamichi; Ching, Chong Thong; Ida, Takeyuki; Itakura, Keiko; Takatani, Setsuo

    1997-06-01

    A new reflectance pulse oximeter sensor for lower arterial oxygen saturation (Sa)2) measurement has been designed and evaluated in animals prior to clinical trials. The new sensor incorporates ten light emitting diode chips for each wavelength of 730 and 880 nm mounted symmetrically and at the radial separation distance of 7 mm around a photodiode chip. The separation distance of 7 mm was chosen to maximize the ratio of the pulsatile to the average plethysmographic signal level at each wavelength. The 730 and 880 wavelength combination was determined to obtain a linear relationship between the reflectance ratio of the 730 and 880 nm wavelengths and Sa)2. In addition to these features of the sensor, the Fast Fourier Transform method was employed to compute the pulsatile and average signal level at each wavelength. The performance of the new reflectance pulse oximeter sensor was evaluated in dogs in comparison to the 665/910 nm sensor. As predicted by the theoretical simulation based on a 3D photon diffusion theory, the 730/880 nm sensor demonstrated an excellent linearity over the SaO2 range from 100 to 30 percent. For the SaO2 range between 100 and 70 percent, the 665/910 and 730/880 sensors showed the standard error of around 3.5 percent and 2.1 percent, respectively, in comparison to the blood samples. For the range between 70 and 30 percent, the standard error of the 730/880 nm sensor was only 2.7 percent, while that of the 665/910 nm sensor was 9.5 percent. The 730/880 sensor showed improved accuracy for a wide range of SaO2 particularly over the range between 70 and 30 percent. This new reflectance sensor can provide noninvasive measurement of SaO2 accurately over the wide saturation range from 100 to 30 percent.

  1. Novel nanostructured materials to develop oxygen-sensitive films for optical sensors

    International Nuclear Information System (INIS)

    Fernandez-Sanchez, Jorge F.; Cannas, Rita; Spichiger, Stefan; Steiger, Rolf; Spichiger-Keller, Ursula E.

    2006-01-01

    Novel nanostructured materials, such as aluminum oxide (AlOOH), silicon oxide (SiO 2 ) or zirconium oxide (ZrO 2 ) embedded into PVA, were investigated as potential matrices to incorporate organometallic compounds (OMCs) for the development of optical oxygen-sensitive sensors which make use of the principle of luminescence quenching. In order to assess the benefits and drawbacks of the nanoporous material, the luminescence quantum yield and the Stern-Volmer constants were investigated and compared with the values shown for the same OMCs solubilized in polymer films (polystyrene). Referred to polymer films, the incorporation of the dyes into nanoporous membranes increased the Stern-Volmer constant by more than a factor of 100. Their response time was less than 1 s and the optode membranes were stable at room temperature for at least 9 months. Sterilization by autoclavation and gamma irradiation resulted in a marginal loss in activity. The photostability and sterilizability of the oxygen-sensitive membranes and the performance of the optodes with respect to of different types of metal oxides are discussed in the paper, as well as the influence of the total pore volume (TPV), the pore diameter (PD), the transparency of the film and the geometry of the pores. The OMCs used in this work were: ETH T -3003 (tris(4,7-bis(4-octylphenyl)-1,10-phenanthroline) ruthenium(II)), N-926 (bis(2-phenylpyridinyl)-N 4 ,N 4 ,N 4 ',N 4 '-tetramethyl-(4,4'-diamine-2,2'-bipyridine) iridium(III) chlorate), N-833 (tetrabutylammonium bis(isothiocyanate) bis(2-phenylpyridinyl)-iridium(III)) and N-837 (tetrabutylammonium bis(cyanate) bis(2-phenylpyridinyl)-iridium(III))

  2. A fibre optic oxygen sensor that detects rapid PO2 changes under simulated conditions of cyclical atelectasis in vitro.

    Science.gov (United States)

    Formenti, Federico; Chen, Rongsheng; McPeak, Hanne; Matejovic, Martin; Farmery, Andrew D; Hahn, Clive E W

    2014-01-15

    Two challenges in the management of Acute Respiratory Distress Syndrome are the difficulty in diagnosing cyclical atelectasis, and in individualising mechanical ventilation therapy in real-time. Commercial optical oxygen sensors can detect [Formula: see text] oscillations associated with cyclical atelectasis, but are not accurate at saturation levels below 90%, and contain a toxic fluorophore. We present a computer-controlled test rig, together with an in-house constructed ultra-rapid sensor to test the limitations of these sensors when exposed to rapidly changing [Formula: see text] in blood in vitro. We tested the sensors' responses to simulated respiratory rates between 10 and 60 breaths per minute. Our sensor was able to detect the whole amplitude of the imposed [Formula: see text] oscillations, even at the highest respiratory rate. We also examined our sensor's resistance to clot formation by continuous in vivo deployment in non-heparinised flowing animal blood for 24h, after which no adsorption of organic material on the sensor's surface was detectable by scanning electron microscopy. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Oxygen sensor equipped engine operation on methanol/gasoline blends and phase separation problems

    Energy Technology Data Exchange (ETDEWEB)

    Last, A J; Lawson, A; Simmons, E W; Mackay, D; Tsang, M; Maund, G B

    1980-01-01

    A study was made to address problems related to Canadian utilization of methanol/gasoline blends. These problems are: (1) cold weather operation; (2) water sensitivity to phase separation in winter; (3) vehicle compatibility: fuel/air ratio control, flexibility for vehicle movement outside of areas where methanol might be available. Specifically, the operation of the HydroShear (an in-line hydraulic emulsifier) on the two separated phases of a methanol/gasoline/water blend was examined. Fuel maps, by engine dynamometer testing, were generated using methanol/gasoline blends containing 15% to 65% methanol. The capability of an oxygen sensor, located in the exhaust system, to control the fuel/air ratio was found to be adequate within the 15% to 65% methanol/gasoline blends. A fuel injected Volvo 244DL with lambda-sond emission control and a carburetted Chevrolet Monza with 3-way catalyst closed loop feedback emission control system were the two engines selected for this study.

  4. Red not dead: signaling in and from erythrocytes.

    Science.gov (United States)

    Sprague, Randy S; Stephenson, Alan H; Ellsworth, Mary L

    2007-11-01

    The oxygen required to meet metabolic needs of all tissues is delivered by the erythrocyte, a small, flexible cell which, in mammals, is devoid of a nucleus and mitochondria. Despite its simple appearance, this 'bag of hemoglobin' has an important role in its own distribution, enabling the delivery of oxygen to precisely meet localized metabolic need. When an erythrocyte enters an area in which tissue oxygen demand exceeds supply, a signaling pathway is activated resulting in the release of adenosine 5'-triphosphate (ATP). This ATP acts in a paracrine fashion to increase vascular caliber resulting in increased oxygen delivery. Defects in this pathway are found in erythrocytes of humans with type 2 diabetes (DM2) and could contribute to the perfusion abnormalities in skeletal muscle associated with this disease.

  5. Physiological variations in levels of 2,3-diphosphoglycerate in horse erythrocytes.

    Science.gov (United States)

    Lewis, I M; McLan, J G

    1975-03-01

    The levels of 2,3-diphosphoglycerate (2,3-DPG), which affects the transport of oxygen by haemoglobin, were examined in horse blood. Resting levels of erythrocyte 2,3-DPG were established in thoroughbred horses, and levels of 2,3-DPG together with haemoglobin levels, were examined in a variety of conditions. A negative correlation was observed between erythrocyte 2,3-DPG and haemoglobin levels. Mares had higher erythrocyte 2,3-DPG levels was observed during training, and this variation may have a significant effect on haemoglobin oxygen transport. Erythrocyte 2,3-DPG levels were not affected by age or exercise.

  6. Crossed Optical Fiber Sensor Arrays for High-Spatial-Resolution Sensing: Application to Dissolved Oxygen Concentration Measurements

    Directory of Open Access Journals (Sweden)

    M. Veronica Rigo

    2012-01-01

    Full Text Available Optical fiber sensors using luminescent probes located along an optical fiber in the cladding of this fiber are of great interest for monitoring physical and chemical properties in their environment. The interrogation of a luminophore with a short laser pulse propagating through the fiber core allows for the measurement of the location of these luminophores. To increase the spatial resolution of such a measurements and to measure multiple analytes and properties in a confined space, a crossed optical fiber sensing platform can be employed. Here we describe the application of this platform to measuring the concentration of dissolved oxygen. The sensor is based on luminescence quenching of a ruthenium complex immobilized in a highly crosslinked film and covalently attached to the optical fibers. Both luminescence-intensity and luminescence-lifetime changes of the sensor molecules in response to changes in the concentration of oxygen dissolved in water are reported. For luminescence-intensity measurements, a second adjacent sensor region is employed as reference to account for laser pulse energy fluctuations. Enhanced quenching response in water is demonstrated by the use of organically modified poly(ethylene glycol precursors, which increase the hydrophobicity of the film surface.

  7. Study and Development of a Fluorescence Based Sensor System for Monitoring Oxygen in Wine Production: The WOW Project.

    Science.gov (United States)

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghesso, Gaudenzio; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe; Cenedese, Angelo

    2018-04-07

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of the winemaking process, both for monitoring and for control. The WOW project (Deployment of WSAN technology for monitoring Oxygen in Wine products) has focused on the design and the development of an innovative device for monitoring the oxygen levels in wine. This system is based on the use of an optical fiber to measure the luminescent lifetime variation of a reference metal/porphyrin complex, which decays in presence of oxygen. The developed technology results in a high sensitivity and low cost sensor head that can be employed for measuring the dissolved oxygen levels at several points inside a wine fermentation or aging tank. This system can be complemented with dynamic modeling techniques to provide predictive behavior of the nutrient evolution in space and time given few sampled measuring points, for both process monitoring and control purposes. The experimental validation of the technology has been first performed in a controlled laboratory setup to attain calibration and study sensitivity with respect to different photo-luminescent compounds and alcoholic or non-alcoholic solutions, and then in an actual case study during a measurement campaign at a renown Italian winery.

  8. Study and Development of a Fluorescence Based Sensor System for Monitoring Oxygen in Wine Production: The WOW Project

    Science.gov (United States)

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe

    2018-01-01

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of the winemaking process, both for monitoring and for control. The WOW project (Deployment of WSAN technology for monitoring Oxygen in Wine products) has focused on the design and the development of an innovative device for monitoring the oxygen levels in wine. This system is based on the use of an optical fiber to measure the luminescent lifetime variation of a reference metal/porphyrin complex, which decays in presence of oxygen. The developed technology results in a high sensitivity and low cost sensor head that can be employed for measuring the dissolved oxygen levels at several points inside a wine fermentation or aging tank. This system can be complemented with dynamic modeling techniques to provide predictive behavior of the nutrient evolution in space and time given few sampled measuring points, for both process monitoring and control purposes. The experimental validation of the technology has been first performed in a controlled laboratory setup to attain calibration and study sensitivity with respect to different photo-luminescent compounds and alcoholic or non-alcoholic solutions, and then in an actual case study during a measurement campaign at a renown Italian winery. PMID:29642468

  9. The oxygen reactivity index and its relation to sensor technology in patients with severe brain lesions.

    Science.gov (United States)

    Dengler, Julius; Frenzel, Christin; Vajkoczy, Peter; Horn, Peter; Wolf, Stefan

    2013-08-01

    The oxygen reactivity index (ORx) has been introduced to assess the status of cerebral autoregulation after traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). Currently, there is some controversy about whether the ORx depends on the type of PbrO2-sensor technology used for its calculation. To examine if the probe technology does matter, we compared the ORx and the resulting optimal cerebral perfusion pressures (CPPopt) of simultaneously implanted Licox (CC1.SB, Integra Neuroscience, France) and Neurovent-PTO (Raumedic, Germany) probes in patients after aneurysmal SAH or severe TBI. Licox and Raumedic probes were implanted side by side in 11 patients after TBI or SAH. ORx and CPPopt were recorded continuously. The equivalence of both probes was examined using Bland-Altman analyses. The mean difference in ORx was 0.1, with Licox producing higher values. The limits of agreement regarding ORx ranged from -0.6 to +0.7. When both probes' ORx values were compared in each patient, no specific pattern in their relationship was seen. The mean difference in CPPopt was 0 mmHg with limits of agreement between -16.5 and +16.4 mmHg. Owing to the rather limited number of patients, we view the results of this study as preliminary. The main result is that Licox and Raumedic showed consistent differences in ORx and CPPopt. Therefore, ORx values of both probes cannot be interchanged and should not be viewed as equivalent. This should be taken into consideration when discussing ORx data generated by different PbrO2 probe types.

  10. An Oxidase-Based Electrochemical Fluidic Sensor with High-Sensitivity and Low-Interference by On-Chip Oxygen Manipulation

    Directory of Open Access Journals (Sweden)

    Chang-Soo Kim

    2012-06-01

    Full Text Available Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide. Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc. to implement a viable component for in-line fluidic sensor systems.

  11. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: Simultaneous oxygen and pH monitoring

    International Nuclear Information System (INIS)

    Liu, Rui; Xiao, Teng; Cui, Weipan; Shinar, Joseph; Shinar, Ruth

    2013-01-01

    Graphical abstract: -- Highlights: •Novel simply-fabricated all-organic electronics pH and oxygen optical monitor. •Excitation sources: directionally emitting, narrowed multicolor microcavity OLEDs. •Photodetectors: small molecule- or polymer-based with selective spectral responses. •Sensor film: structured high molecular weight polystyrene:polyethylene glycol blend. •×1.9 sensitivity enhancement and ×2.7 increase in the photoluminescence for oxygen. -- Abstract: Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs’ broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ∼20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ 0 /τ 100 (PL decay time τ at 0% O 2 /τ at 100% O 2 ) that is often used to express S

  12. Oxidative Hemolysis of Erythrocytes

    Science.gov (United States)

    Wlodek, Lidia; Kusior, Dorota

    2006-01-01

    This exercise for students will allow them to simultaneously observe lipid peroxidation and consequent hemolysis of rat erythrocytes and the effect of sodium azide, a catalase inhibitor, on these processes. It will also demonstrate a protective action of antioxidants, the therapeutically used N-acetylcysteine and albumins present in plasma.

  13. The Role of Oxygen Sensors, Hydroxylases, and HIF in Cardiac Function and Disease

    Directory of Open Access Journals (Sweden)

    W. H. Davin Townley-Tilson

    2015-01-01

    Full Text Available Ischemic heart disease is the leading cause of death worldwide. Oxygen-sensing proteins are critical components of the physiological response to hypoxia and reperfusion injury, but the role of oxygen and oxygen-mediated effects is complex in that they can be cardioprotective or deleterious to the cardiac tissue. Over 200 oxygen-sensing proteins mediate the effects of oxygen tension and use oxygen as a substrate for posttranslational modification of other proteins. Hydroxylases are an essential component of these oxygen-sensing proteins. While a major role of hydroxylases is regulating the transcription factor HIF, we investigate the increasing scope of hydroxylase substrates. This review discusses the importance of oxygen-mediated effects in the heart as well as how the field of oxygen-sensing proteins is expanding, providing a more complete picture into how these enzymes play a multifaceted role in cardiac function and disease. We also review how oxygen-sensing proteins and hydroxylase function could prove to be invaluable in drug design and therapeutic targets for heart disease.

  14. Clofazimine Induced Suicidal Death of Human Erythrocytes

    Directory of Open Access Journals (Sweden)

    Arbace Officioso

    2015-08-01

    Full Text Available Background/Aims: The antimycobacterial riminophenazine clofazimine has previously been shown to up-regulate cellular phospholipase A2 and to induce apoptosis. In erythrocytes phospholipase A2 stimulates eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Phospholipase A2 is in part effective by fostering formation of prostaglandin E2, which triggers Ca2+ entry. Stimulators of Ca2+ entry and eryptosis further include oxidative stress and energy depletion. The present study tested, whether and how clofazimine induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, hemolysis from hemoglobin release, cytosolic Ca2+ activity ([Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS from 2′, 7′-dichlorodihydrofluorescein diacetate (DCFDA fluorescence, and cytosolic ATP level utilizing a luciferin-luciferase assay kit. Results: A 24-48 hours exposure of human erythrocytes to clofazimine (≥1.5 µg/ml significantly increased the percentage of annexin-V-binding cells without appreciably modifying forward scatter. Clofazimine significantly increased [Ca2+]i, significantly decreased cytosolic ATP, but did not significantly modify ROS. The effect of clofazimine on annexin-V-binding was significantly blunted, but not fully abolished by removal of extracellular Ca2+, and by phospholipase A2 inhibitor quinacrine (25 µM. Clofazimine further augmented the effect of Ca2+ ionophore ionomycin (0.1 µM on eryptosis. The clofazimine induced annexin-V-binding was, however, completely abrogated by combined Ca2+ removal and addition of quinacrine. Conclusion: Clofazimine stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect in part dependent on entry of extracellular Ca2+, paralleled by cellular energy depletion and sensitive to

  15. Acute dark chocolate ingestion is beneficial for hemodynamics via enhancement of erythrocyte deformability in healthy humans.

    Science.gov (United States)

    Radosinska, Jana; Horvathova, Martina; Frimmel, Karel; Muchova, Jana; Vidosovicova, Maria; Vazan, Rastislav; Bernatova, Iveta

    2017-03-01

    Erythrocyte deformability is an important property of erythrocytes that considerably affects blood flow and hemodynamics. The high content of polyphenols present in dark chocolate has been reported to play a protective role in functionality of erythrocytes. We hypothesized that chocolate might influence erythrocytes not only after repeated chronic intake, but also immediately after its ingestion. Thus, we determined the acute effect of dark chocolate and milk (with lower content of biologically active substances) chocolate intake on erythrocyte deformability. We also focused on selected factors that may affect erythrocyte deformability, specifically nitric oxide production in erythrocytes and total antioxidant capacity of plasma. We determined posttreatment changes in the mentioned parameters 2hours after consumption of chocolate compared with their levels before consumption of chocolate. In contrast to milk chocolate intake, the dark chocolate led to a significantly higher increase in erythrocyte deformability. Nitric oxide production in erythrocytes was not changed after dark chocolate intake, but significantly decreased after milk chocolate. The plasma total antioxidant capacity remained unaffected after ingestion of both chocolates. We conclude that our hypothesis was confirmed. Single ingestion of dark chocolate improved erythrocyte deformability despite unchanged nitric oxide production and antioxidant capacity of plasma. Increased deformability of erythrocytes may considerably improve rheological properties of blood and thus hemodynamics in humans, resulting in better tissue oxygenation. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Erythrocyte nanovesicles: Biogenesis, biolo

    Directory of Open Access Journals (Sweden)

    Gamaleldin I. Harisa

    2017-01-01

    Full Text Available Nanovesicles (NVs represent a novel transporter for cell signals to modify functions of target cells. Therefore, NVs play many roles in both physiological and pathological processes. This report highlights biogenesis, composition and biological roles of erythrocytes derived nanovesicles (EDNVs. Furthermore, we address utilization of EDNVs as novel drug delivery cargo as well as therapeutic target. EDNVs are lipid bilayer vesicles rich in phospholipids, proteins, lipid raft, and hemoglobin. In vivo EDNVs biogenesis is triggered by an increase of intracellular calcium levels, ATP depletion and under effect of oxidative stress conditions. However, in vitro production of EDNVs can be achieved via hypotonic treatment and extrusion of erythrocyte. NVs can be used as biomarkers for diagnosis, monitoring of therapy and drug delivery system. Many therapeutic agents are suggested to decrease NVs biogenesis.

  17. Enhanced response of microbial fuel cell using sulfonated poly ether ether ketone membrane as a biochemical oxygen demand sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ayyaru, Sivasankaran; Dharmalingam, Sangeetha, E-mail: sangeetha@annauniv.edu

    2014-03-01

    Graphical abstract: - Highlights: • Sulfonated poly ether ether ketone (SPEEK) membrane in SCMFC used to determine the BOD. • The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm. • This sensing range was 62.5% higher than that of Nafion{sup ®}. • SPEEK exhibited one order lesser oxygen permeability than Nafion{sup ®}. • Nafion{sup ®} shows high anodic internal resistance (67 Ω) than the SPEEK (39 Ω). - Abstract: The present study is focused on the development of single chamber microbial fuel cell (SCMFC) using sulfonated poly ether ether ketone (SPEEK) membrane to determine the biochemical oxygen demand (BOD) matter present in artificial wastewater (AW). The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm when using artificial wastewater. This sensing range was 62.5% higher than that of Nafion{sup ®}. The most serious problem in using MFC as a BOD sensor is the oxygen diffusion into the anode compartment, which consumes electrons in the anode compartment, thereby reducing the coulomb yield and reducing the electrical signal from the MFC. SPEEK exhibited one order lesser oxygen permeability than Nafion{sup ®}, resulting in low internal resistance and substrate loss, thus improving the sensing range of BOD. The system was further improved by making a double membrane electrode assembly (MEA) with an increased electrode surface area which provide high surface area for electrically active bacteria.

  18. Acute isovolemic hemodilution triggers proinflammatory and procoagulatory endothelial activation in vital organs : Role of erythrocyte aggregation

    NARCIS (Netherlands)

    Morariu, Aurora M.; Maathuis, Mark-Hugo J.; Asgeirsdottir, Sigridur A.; Leuvenink, Henri G. D.; Boonstra, Piet W.; Van Oeveren, Wim; Ploeg, Rutger J.; Molema, Ingrid; Rakhorst, Gerhard

    2006-01-01

    Objectives: The essential role of erythrocytes as oxygen carriers is historically well established, but their function to aggregate and the consequences on the microcirculation is under debate. The pathogenic potential of low erythrocyte aggregation could be important for patients undergoing on-pump

  19. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: simultaneous oxygen and pH monitoring.

    Science.gov (United States)

    Liu, Rui; Xiao, Teng; Cui, Weipan; Shinar, Joseph; Shinar, Ruth

    2013-05-17

    Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs' broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ~20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ0/τ100 (PL decay time τ at 0% O2/τ at 100% O2) that is often used to express S increases ×1.9 to 20.7 relative to the lower molecular weight PS, where this ratio is 11.0. This increase reduces to ×1.7 when the PEG is added (τ0/τ100=18.2), but the latter results in an increase ×2.7 in the PL intensity. The sensor's response time is <10s in all cases. The microporous structure of these blended films, with PEG decorating PS pores, serves a dual purpose. It results in light scattering that reduces the EL that is waveguided in the substrate of the OLEDs and

  20. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: Simultaneous oxygen and pH monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui; Xiao, Teng; Cui, Weipan [Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Shinar, Joseph, E-mail: jshinar@iastate.edu [Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Shinar, Ruth, E-mail: rshinar@iastate.edu [Microelectronics Research Center and Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011 (United States)

    2013-05-17

    Graphical abstract: -- Highlights: •Novel simply-fabricated all-organic electronics pH and oxygen optical monitor. •Excitation sources: directionally emitting, narrowed multicolor microcavity OLEDs. •Photodetectors: small molecule- or polymer-based with selective spectral responses. •Sensor film: structured high molecular weight polystyrene:polyethylene glycol blend. •×1.9 sensitivity enhancement and ×2.7 increase in the photoluminescence for oxygen. -- Abstract: Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs’ broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ∼20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ{sub 0}/τ{sub 100} (PL decay time τ at 0% O{sub 2}/τ at 100% O{sub 2}) that is often used

  1. Microencapsulated 3-dimensional sensor for the measurement of oxygen in single isolated pancreatic islets.

    Directory of Open Access Journals (Sweden)

    Wanyu Chen

    Full Text Available Oxygen consumption reflects multiple processes in pancreatic islets including mechanisms contributing to insulin secretion, oxidative stress and viability, providing an important readout in studies of islet function, islet viability and drug testing. Due to the scarcity, heterogeneity, and intrinsic kinetic properties of individual islets, it would be of great benefit to detect oxygen consumption by single islets. We present a novel method we have developed to image oxygen in single islets.Using a microfluidics system, individual islets and a fluorescent oxygen-sensitive dye were encased within a thin alginate polymer layer. Insulin secretion by the encapsulated islets was normal. Fluorescent signal from the encased dye, detected using a standard inverted fluorescence microscope and digital camera, was stable and proportional to the amount of oxygen in the media. When integrated into a perifusion system, the sensing system detected changes in response to metabolic substrates, mitochondrial poisons, and induced-oscillations. Glucose responses averaged 30.1±7.1% of the response to a metabolic inhibitor (cyanide, increases were observed in all cases (n = 6, and the system was able to resolve changes in oxygen consumption that had a period greater than 0.5 minutes. The sensing system operated similarly from 2-48 hours following encapsulation, and viability and function of the islets were not significantly affected by the encapsulation process.An oxygen-dependent dye situated around and within a pancreatic islet encapsulated by a thin layer of alginate was sensitive to changes in oxygen consumption, and was not harmful to the function or viability of islets over the course of two days. The microcapsule-based sensing method is particularly suited to assessing the effects of compounds (dose responses and time courses and chronic changes occurring over the course of days. The approach should be applicable to other cell types and dyes sensitive to other

  2. Microencapsulated 3-Dimensional Sensor for the Measurement of Oxygen in Single Isolated Pancreatic Islets

    Science.gov (United States)

    Khalil, Gamal; Sweet, Ian R.; Shen, Amy Q.

    2012-01-01

    Background Oxygen consumption reflects multiple processes in pancreatic islets including mechanisms contributing to insulin secretion, oxidative stress and viability, providing an important readout in studies of islet function, islet viability and drug testing. Due to the scarcity, heterogeneity, and intrinsic kinetic properties of individual islets, it would be of great benefit to detect oxygen consumption by single islets. We present a novel method we have developed to image oxygen in single islets. Methodology/Principal Findings Using a microfluidics system, individual islets and a fluorescent oxygen-sensitive dye were encased within a thin alginate polymer layer. Insulin secretion by the encapsulated islets was normal. Fluorescent signal from the encased dye, detected using a standard inverted fluorescence microscope and digital camera, was stable and proportional to the amount of oxygen in the media. When integrated into a perifusion system, the sensing system detected changes in response to metabolic substrates, mitochondrial poisons, and induced-oscillations. Glucose responses averaged 30.1±7.1% of the response to a metabolic inhibitor (cyanide), increases were observed in all cases (n = 6), and the system was able to resolve changes in oxygen consumption that had a period greater than 0.5 minutes. The sensing system operated similarly from 2–48 hours following encapsulation, and viability and function of the islets were not significantly affected by the encapsulation process. Conclusions/Significance An oxygen-dependent dye situated around and within a pancreatic islet encapsulated by a thin layer of alginate was sensitive to changes in oxygen consumption, and was not harmful to the function or viability of islets over the course of two days. The microcapsule-based sensing method is particularly suited to assessing the effects of compounds (dose responses and time courses) and chronic changes occurring over the course of days. The approach should be

  3. A highly sensitive amperometric sensor for oxygen based on iron(II) tetrasulfonated phthalocyanine and iron(III) tetra-(N-methyl-pyridyl)-porphyrin multilayers

    International Nuclear Information System (INIS)

    Duarte, Juliana C.; Luz, Rita C.S.; Damos, Flavio S.; Tanaka, Auro A.; Kubota, Lauro T.

    2008-01-01

    The development of a highly sensitive sensor for oxygen is proposed using a glassy carbon (GC) electrode modified with alternated layers of iron(II) tetrasulfonated phthalocyanine (FeTsPc) and iron(III) tetra-(N-methyl-pyridyl)-porphyrin (FeT4MPyP). The modified electrode showed excellent catalytic activity for the oxygen reduction. The reduction potential of the oxygen was shifted about 330 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare GC electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves 4 electrons with a heterogenous rate constant (k obs ) of 3 x 10 5 mol -1 L s -1 . A linear response range from 0.2 up to 6.4 mg L -1 , with a sensitivity of 4.12 μA L mg -1 (or 20.65 μA cm -2 L mg -1 ) and a detection limit of 0.06 mg L -1 were obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation (R.S.D.) was 2.0% for 10 measurements of a solution of 6.4 mg L -1 oxygen. The sensor was applied to determine oxygen in pond and tap water samples showing to be a promising tool for this purpose

  4. A Micro Oxygen Sensor Based on a Nano Sol-Gel TiO2 Thin Film

    Directory of Open Access Journals (Sweden)

    Hairong Wang

    2014-09-01

    Full Text Available An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 μm × 350 μm was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor’s output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10−4 and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required.

  5. A Macroporous TiO2 Oxygen Sensor Fabricated Using Anodic Aluminium Oxide as an Etching Mask

    Directory of Open Access Journals (Sweden)

    Sheng-Po Wu

    2010-01-01

    Full Text Available An innovative fabrication method to produce a macroporous Si surface by employing an anodic aluminium oxide (AAO nanopore array layer as an etching template is presented. Combining AAO with a reactive ion etching (RIE processes, a homogeneous and macroporous silicon surface can be effectively configured by modulating AAO process parameters and alumina film thickness, thus hopefully replacing conventional photolithography and electrochemical etch methods. The hybrid process integration is considered fully CMOS compatible thanks to the low-temperature AAO and CMOS processes. The gas-sensing characteristics of 50 nm TiO2 nanofilms deposited on the macroporous surface are compared with those of conventional plain (or non-porous nanofilms to verify reduced response noise and improved sensitivity as a result of their macroporosity. Our experimental results reveal that macroporous geometry of the TiO2 chemoresistive gas sensor demonstrates 2-fold higher (~33% improved sensitivity than a non-porous sensor at different levels of oxygen exposure. In addition, the macroporous device exhibits excellent discrimination capability and significantly lessened response noise at 500 °C. Experimental results indicate that the hybrid process of such miniature and macroporous devices are compatible as well as applicable to integrated next generation bio-chemical sensors.

  6. Injectable LiNc-BuO loaded microspheres as in vivo EPR oxygen sensors after co-implantation with tumor cells.

    Science.gov (United States)

    Frank, Juliane; Gündel, Daniel; Drescher, Simon; Thews, Oliver; Mäder, Karsten

    2015-12-01

    Electron paramagnetic resonance (EPR) oximetry is a technique which allows accurate and repeatable oxygen measurements. We encapsulated a highly oxygen sensitive particulate EPR spin probe into microparticles to improve its dispersibility and, hence, facilitate the administration. These biocompatible, non-toxic microspheres contained 5-10 % (w/w) spin probe and had an oxygen sensitivity of 0.60 ± 0.01 µT/mmHg. To evaluate the performance of the microparticles as oxygen sensors, they were co-implanted with syngeneic tumor cells in 2 different rat strains. Thus, tissue injury was avoided and the microparticles were distributed all over the tumor tissue. Dynamic changes of the intratumoral oxygen partial pressure during inhalation of 8 %, 21 %, or 100 % oxygen were monitored in vivo by EPR spectroscopy and quantified. Values were verified in vivo by invasive fluorometric measurements using Oxylite probes and ex vivo by pimonidazole adduct accumulation. There were no hints that the tumor physiology or tissue oxygenation had been altered by the microparticles. Hence, these microprobes offer great potential as oxygen sensors in preclinical research, not only for EPR spectroscopy but also for EPR imaging. For instance, the assessment of tissue oxygenation during therapeutic interventions might help understanding pathophysiological processes and lead to an individualized treatment planning or the use of formulations with hypoxia triggered release of active agents. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Improvement in the Sensitivity of PbO Doped Tin Oxide Thick Film Gas Sensor by RF and Microwave Oxygen Plasma Treatment

    Directory of Open Access Journals (Sweden)

    J. K. SRIVASTAVA

    2010-07-01

    Full Text Available In the present work efforts have been made to analyze the effect of oxygen plasma and PbO doping on the sensitivity of SnO2-based thick film gas sensor for methanol, propanol and acetone. The effect of substrate temperature on the response of dual frequency (RF and microwave plasma treated thick film sensor array has also been studied. To achieve this, three sensor arrays (each with four tin oxide sensors doped with different (1 %, 2 %, 3 % and 4 % PbO concentrations were fabricated by thick film technology and then treated with oxygen plasma for various durations (5 min, 10 min. and 15 min.. The plasma treated sensors were found to possess appreciably high sensitivity at room temperature in comparison to untreated sensor. The sensitivity showed the increasing trend with plasma exposure time and 15 minutes exposure time was found to be most suitable as the sensitivity of the plasma treated sensors for this duration were high towards all the chosen vapors with maximum (97 % value for propanol. The sensitivity of the sensors were found to be increasing gradually as PbO concentration was varied from 1- 4%.

  8. Fucoxanthin Induced Suicidal Death of Human Erythrocytes

    Directory of Open Access Journals (Sweden)

    Marilena Briglia

    2015-12-01

    Full Text Available Background/Aims: Fucoxanthin, a carotenoid isolated from brown seaweeds, induces suicidal death or apoptosis of tumor cells and is thus considered for the treatment or prevention of malignancy. In analogy to apoptosis of nucleated cell, erythrocytes may enter eryptosis, the suicidal death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include Ca2+ entry with increase of cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and activation of p38 kinase or protein kinase C. The present study explored, whether and how fucoxanthin induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, and abundance of reactive oxygen species (ROS from DCFDA dependent fluorescence and lipid peroxidation using BODIPY fluoresence. Results: A 48 hours exposure of human erythrocytes to fucoxanthin significantly increased the percentage of annexin-V-binding cells (≥ 50 µM, significantly decreased average forward scatter (≥ 25 µM, significantly increased hemolysis (≥ 25 µM, significantly increased Fluo3-fluorescence (≥ 50 µM, significantly increased lipid peroxidation, but did not significantly modify DCFDA fluorescence. The effect of fucoxanthin on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+, and was insensitive to p38 kinase inhibitor skepinone (2 µM and to protein kinase C inhibitor calphostin (100 nM. Conclusion: Fucoxanthin triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to stimulation of Ca2+ entry.

  9. The Determination of the Percent of Oxygen in Air Using a Gas Pressure Sensor

    Science.gov (United States)

    Gordon, James; Chancey, Katherine

    2005-01-01

    The experiment of determination of the percent of oxygen in air is performed in a general chemistry laboratory in which students compare the results calculated from the pressure measurements obtained with the calculator-based systems to those obtained in a water-measurement method. This experiment allows students to explore a fundamental reaction…

  10. Dielectric inspection of erythrocyte morphology

    International Nuclear Information System (INIS)

    Hayashi, Yoshihito; Oshige, Ikuya; Katsumoto, Yoichi; Omori, Shinji; Yasuda, Akio; Asami, Koji

    2008-01-01

    We performed a systematic study of the sensitivity of dielectric spectroscopy to erythrocyte morphology. Namely, rabbit erythrocytes of four different shapes were prepared by precisely controlling the pH of the suspending medium, and their complex permittivities over the frequency range from 0.1 to 110 MHz were measured and analyzed. Their quantitative analysis shows that the characteristic frequency and the broadening parameter of the dielectric relaxation of interfacial polarization are highly specific to the erythrocyte shape, while they are insensitive to the cell volume fraction. Therefore, these two dielectric parameters can be used to differentiate erythrocytes of different shapes, if dielectric spectroscopy is applied to flow-cytometric inspection of single blood cells. In addition, we revealed the applicability and limitations of the analytical theory of interfacial polarization to explain the experimental permittivities of non-spherical erythrocytes

  11. Dielectric inspection of erythrocyte morphology

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Yoshihito; Oshige, Ikuya; Katsumoto, Yoichi; Omori, Shinji; Yasuda, Akio [Life Science Laboratory, Materials Laboratories, Sony Corporation, Sony Bioinformatics Center, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510 (Japan); Asami, Koji [Laboratory of Molecular Aggregation Analysis, Division of Multidisciplinary Chemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)], E-mail: Yoshihito.Hayashi@jp.sony.com

    2008-05-21

    We performed a systematic study of the sensitivity of dielectric spectroscopy to erythrocyte morphology. Namely, rabbit erythrocytes of four different shapes were prepared by precisely controlling the pH of the suspending medium, and their complex permittivities over the frequency range from 0.1 to 110 MHz were measured and analyzed. Their quantitative analysis shows that the characteristic frequency and the broadening parameter of the dielectric relaxation of interfacial polarization are highly specific to the erythrocyte shape, while they are insensitive to the cell volume fraction. Therefore, these two dielectric parameters can be used to differentiate erythrocytes of different shapes, if dielectric spectroscopy is applied to flow-cytometric inspection of single blood cells. In addition, we revealed the applicability and limitations of the analytical theory of interfacial polarization to explain the experimental permittivities of non-spherical erythrocytes.

  12. Effect of oxygen and hydrogen on the optical and electrical characteristics of porous silicon. Towards sensor applications

    International Nuclear Information System (INIS)

    Green, S.

    2000-02-01

    The effect of adsorbed oxygen and hydrogen gas on porous silicon has been investigated using two different techniques, viz. optical and electrical. The photoluminescence quenching by oxygen and hydrogen was found to be reversible with a response time of the order of 3000 s. Unlike any reported porous silicon gas quenching systems, both the extent and rate of quenching were found to be a function of photoluminescence wavelength. The quenching is attributed to charge transfer from the conduction band of porous silicon to the lowest unoccupied molecular orbital of oxygen and hydrogen, respectively. Surface conductance measurements (aluminium contacts) show that the principal charge transfer process is via tunnelling, with some conduction through the underlying bulk p-type silicon layer. Symmetrical current-voltage plots were obtained for this system which were attributed to pinning of the aluminium-porous silicon Fermi level at mid-gap by the high surface trap density. An approximate doubling of the aluminium electrode separation was found to reduce approximately fourfold the initial rate of increase in surface conductance on adsorption of oxygen at a pressure of 10 torr. To the best of the author's knowledge this is the first time that such an effect has been reported in a room temperature solid state gas sensor. Gas sensitivity measurements using surface contacts show a logarithmic response to the concentration of oxygen up to a pressure of 100 torr with a rapid response, of 300 s. A 39% increase in surface conductance occurs on exposure of the device to 100 torr of oxygen. The surface conductance of the device decreases by 34% on exposure to one atmosphere of hydrogen with a response time of the order 2000 s. Transverse conductance (DC) measurements show that Au/PS/p-Si/Al..Ag devices behave like a field-dependent diode. An admittance spectroscopy technique has been applied to porous silicon for the first time to calculate g 0 , the trap density at the Fermi level

  13. Role of distal arginine in early sensing intermediates in the heme domain of the oxygen sensor FixL.

    Science.gov (United States)

    Jasaitis, Audrius; Hola, Klara; Bouzhir-Sima, Latifa; Lambry, Jean-Christophe; Balland, Veronique; Vos, Marten H; Liebl, Ursula

    2006-05-16

    FixL is a bacterial heme-based oxygen sensor, in which release of oxygen from the sensing PAS domain leads to activation of an associated kinase domain. Static structural studies have suggested an important role of the conserved residue arginine 220 in signal transmission at the level of the heme domain. To assess the role of this residue in the dynamics and properties of the initial intermediates in ligand release, we have investigated the effects of R220X (X = I, Q, E, H, or A) mutations in the FixLH heme domain on the dynamics and spectral properties of the heme upon photolysis of O(2), NO, and CO using femtosecond transient absorption spectroscopy. Comparison of transient spectra for CO and NO dissociation with steady-state spectra indicated less strain on the heme in the ligand dissociation species for all mutants compared to the wild type (WT). For CO and NO, the kinetics were similar to those of the wild type, with the exception of (1) a relatively low yield of picosecond NO rebinding to R220A, presumably related to the increase in the free volume of the heme pocket, and (2) substantial pH-dependent picosecond to nanosecond rebinding of CO to R220H, related to formation of a hydrogen bond between CO and histidine 220. Upon excitation of the complex bound with the physiological sensor ligand O(2), a 5-8 ps decay phase and a nondecaying (>4 ns) phase were observed for WT and all mutants. The strong distortion of the spectrum associated with the decay phase in WT is substantially diminished in all mutant proteins, indicating an R220-induced role of the heme in the primary intermediate in signal transmission. Furthermore, the yield of dissociated oxygen after this phase ( approximately 10% in WT) is increased in all mutants, up to almost unity in R220A, indicating a key role of R220 in caging the oxygen near the heme through hydrogen bonding. Molecular dynamics simulations corroborate these findings and suggest motions of O(2) and arginine 220 away from the heme

  14. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers

    OpenAIRE

    Mathupala, Saroj P.; Kiousis, Sam; Szerlip, Nicholas J.

    2016-01-01

    Background Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system t...

  15. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  16. A multiplexed electronic architecture for opto-electronic patch sensor to effectively monitor heart rate and oxygen saturation

    Science.gov (United States)

    Yan, Liangwen; Hu, Sijung; Alharbi, Samah; Blanos, Panagiotis

    2018-02-01

    To effectively capture human vital signs, a multi-wavelength optoelectronic patch sensor (MOEPS), together with a schematic architecture of electronics, was developed to overcome the drawbacks of present photoplethysmographic (PPG) sensors. To obtain a better performance of in vivo physiological measurement, the optimal illuminations, i.e., light emitting diodes (LEDs) in the MOEPS, whose wavelength is automatically adjusted to each specific subject, were selected to capture better PPG signals. A multiplexed electronic architecture has been well established to properly drive the MOEPS and effectively capture pulsatile waveforms at rest. The protocol was designed to investigate its performance with the participation of 11 healthy subjects aged between 18 and 30. The signals obtained from green (525nm) and orange (595nm) illuminations were used to extract heart rate (HR) and oxygen saturation (SpO2%). These results were compared with data, simultaneously acquired, from a commercial ECG and a pulse oximeter. Considering the difficulty for current devices to attain the SpO2%, a new computing method, to obtain the value of SpO2%, is proposed depended on the green and orange wavelength illuminations. The values of SpO2% between the MOEPS and the commercial Pulse Oximeter devics showed that the results were in good agreement. The values of HR showed close correlation between commercial devices and the MOEPS (HR: r1=0.994(Green); r2=0.992(Orange); r3=0.975(Red); r4=0.990(IR)).

  17. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers

    Science.gov (United States)

    Mathupala, Saroj P.; Kiousis, Sam; Szerlip, Nicholas J.

    2016-01-01

    Background Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system to monitor gas-phase O2, the cell-based data tend to be non-uniform due to the ad hoc nature of the experimental setup. Methodology With the availability of low-cost open-source microcontroller-based electronic project kits, it is now possible for researchers to program these with easy-to-use software, link them to sensors, and place them in basic scientific apparatus to monitor and record experimental parameters. We report here the design and construction of a small-footprint kit for continuous measurement and recording of O2 concentration in modular hypoxia chambers. The low-cost assembly (US$135) consists of an Arduino-based microcontroller, data-logging freeware, and a factory pre-calibrated miniature O2 sensor. A small, intuitive software program was written by the authors to control the data input and output. The basic nature of the kit will enable any student in biology with minimal experience in hobby-electronics to assemble the system and edit the program parameters to suit individual experimental conditions. Results/Conclusions We show the kit’s utility and stability of data output via a series of hypoxia experiments. The studies also demonstrated the critical need to monitor and adjust gas-phase O2 concentration during hypoxia-based experiments to prevent experimental errors or failure due to partial loss of hypoxia. Thus, incorporating the sensor-microcontroller module to a portable hypoxia chamber provides a researcher a capability that was previously available

  18. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers.

    Directory of Open Access Journals (Sweden)

    Saroj P Mathupala

    Full Text Available Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system to monitor gas-phase O2, the cell-based data tend to be non-uniform due to the ad hoc nature of the experimental setup.With the availability of low-cost open-source microcontroller-based electronic project kits, it is now possible for researchers to program these with easy-to-use software, link them to sensors, and place them in basic scientific apparatus to monitor and record experimental parameters. We report here the design and construction of a small-footprint kit for continuous measurement and recording of O2 concentration in modular hypoxia chambers. The low-cost assembly (US$135 consists of an Arduino-based microcontroller, data-logging freeware, and a factory pre-calibrated miniature O2 sensor. A small, intuitive software program was written by the authors to control the data input and output. The basic nature of the kit will enable any student in biology with minimal experience in hobby-electronics to assemble the system and edit the program parameters to suit individual experimental conditions.We show the kit's utility and stability of data output via a series of hypoxia experiments. The studies also demonstrated the critical need to monitor and adjust gas-phase O2 concentration during hypoxia-based experiments to prevent experimental errors or failure due to partial loss of hypoxia. Thus, incorporating the sensor-microcontroller module to a portable hypoxia chamber provides a researcher a capability that was previously available only to labs with access to

  19. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers.

    Science.gov (United States)

    Mathupala, Saroj P; Kiousis, Sam; Szerlip, Nicholas J

    2016-01-01

    Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system to monitor gas-phase O2, the cell-based data tend to be non-uniform due to the ad hoc nature of the experimental setup. With the availability of low-cost open-source microcontroller-based electronic project kits, it is now possible for researchers to program these with easy-to-use software, link them to sensors, and place them in basic scientific apparatus to monitor and record experimental parameters. We report here the design and construction of a small-footprint kit for continuous measurement and recording of O2 concentration in modular hypoxia chambers. The low-cost assembly (US$135) consists of an Arduino-based microcontroller, data-logging freeware, and a factory pre-calibrated miniature O2 sensor. A small, intuitive software program was written by the authors to control the data input and output. The basic nature of the kit will enable any student in biology with minimal experience in hobby-electronics to assemble the system and edit the program parameters to suit individual experimental conditions. We show the kit's utility and stability of data output via a series of hypoxia experiments. The studies also demonstrated the critical need to monitor and adjust gas-phase O2 concentration during hypoxia-based experiments to prevent experimental errors or failure due to partial loss of hypoxia. Thus, incorporating the sensor-microcontroller module to a portable hypoxia chamber provides a researcher a capability that was previously available only to labs with access to sophisticated (and

  20. Enzymatic oxidation of mercury vapor by erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Halbach, S; Clarkson, T W

    1978-01-01

    The formation of glutathione radicals, the evolution of nascent oxygen or the peroxidatic reaction with catalase complex I are considered as possible mechanisms for the oxidation of mercury vapor by red blood cells. To select among these, the uptake of atomic mercury by erythrocytes from different species was studied and related to their various activities of catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase, EC 1.11.1.6) and glutathione peroxidase (glutathione:hydrogen-peroxide oxidoreductase, EC 1.11.1.9). A slow and continuouus infusion of diluted H/sub 2/O/sub 2/ was used to maintain steady concentrations of complex I. 1% red cell suspensions were found most suitable showing high rates of Hg uptake and yielding still enough cells for subsequent determinations. The results indicate that the oxidation of mercury depends upon the H/sub 2/O/sub 2/-generation rate and upon the specific acticity of red-cell catalase. The oxidation occurred in a range of the catalase-H/sub 2/O/sub 2/ reaction where the evolution of oxygen could be excluded. Compounds reacting with complex I were shown to be effective inhibitors of the mercury uptake. GSH-peroxidase did not participate in the oxidation but rather, was found to inhibit it by competing with catalase for hydrogen peroxide. These findings support the view that elemental mercury is oxidized in erythrocytes by a peroxidatic reaction with complex I only.

  1. Optical Assay of Erythrocyte Function in Banked Blood

    Science.gov (United States)

    Bhaduri, Basanta; Kandel, Mikhail; Brugnara, Carlo; Tangella, Krishna; Popescu, Gabriel

    2014-09-01

    Stored red blood cells undergo numerous biochemical, structural, and functional changes, commonly referred to as storage lesion. How much these changes impede the ability of erythrocytes to perform their function and, as result, impact clinical outcomes in transfusion patients is unknown. In this study we investigate the effect of the storage on the erythrocyte membrane deformability and morphology. Using optical interferometry we imaged red blood cell (RBC) topography with nanometer sensitivity. Our time-lapse imaging quantifies membrane fluctuations at the nanometer scale, which in turn report on cell stiffness. This property directly impacts the cell's ability to transport oxygen in microvasculature. Interestingly, we found that cells which apparently maintain their normal shape (discocyte) throughout the storage period, stiffen progressively with storage time. By contrast, static parameters, such as mean cell hemoglobin content and morphology do not change during the same period. We propose that our method can be used as an effective assay for monitoring erythrocyte functionality during storage time.

  2. Low Power Resistive Oxygen Sensor Based on Sonochemical SrTi0.6Fe0.4O2.8 (STFO40

    Directory of Open Access Journals (Sweden)

    Alisa Stratulat

    2015-07-01

    Full Text Available The current paper reports on a sonochemical synthesis method for manufacturing nanostructured (typical grain size of 50 nm SrTi0.6Fe0.4O2.8 (Sono-STFO40 powder. This powder is characterized using X ray-diffraction (XRD, Mössbauer spectroscopy and Scanning Electron Microscopy (SEM, and results are compared with commercially available SrTi0.4Fe0.6O2.8 (STFO60 powder. In order to manufacture resistive oxygen sensors, both Sono-STFO40 and STFO60 are deposited, by dip-pen nanolithography (DPN method, on an SOI (Silicon-on-Insulator micro-hotplate, employing a tungsten heater embedded within a dielectric membrane. Oxygen detection tests are performed in both dry (RH = 0% and humid (RH = 60% nitrogen atmosphere, varying oxygen concentrations between 1% and 16% (v/v, at a constant heater temperature of 650 °C. The oxygen sensor, based on the Sono-STFO40 sensing layer, shows good sensitivity, low power consumption (80 mW, and short response time (25 s. These performance are comparable to those exhibited by state-of-the-art O2 sensors based on STFO60, thus proving Sono-STFO40 to be a material suitable for oxygen detection in harsh environments.

  3. The Effects of Electromagnetic Fields Generated from 1800 MHz Cell Phones on Erythrocyte Rheological Parameters and Zinc Level in Rats

    Directory of Open Access Journals (Sweden)

    Ümit Divrikli

    2012-06-01

    Full Text Available Objective: The aim of this study was to investigate the effects of the electromagnetic field generated from the 1800 MHz radiofrequency radiation (EF on erythrocyte rheological parameters and erythrocyte zinc levels. Material and Methods: Twenty-four male Wistar Albino rats were randomly grouped as follows: 1 two control groups and 2 study groups: i Group A: EF exposed group (2.5 h/day for 30 days, the phone on stand-by, and ii Group B: EF exposed group (2.5 min/day for 30 days, the phone ringing in silent mode. At the end of the experimental period erythrocyte rheological parameters such as erythrocyte deformability and aggregation were determined by an ectacytometer. Erythrocyte zinc level, which affects hemorheological parameters, was also measured by atomic absorption spectrophotometer. Results: Erythrocyte deformability was decreased in both study groups but the decrease in group A was not statistically significant. Exposure to EF did not have any significant effect on erythrocyte aggregation. On the other hand, erythrocyte zinc level was significantly reduced in both study groups. Conclusion: Exposure to EF may have decreased tissue oxygenation due to reduced erythrocyte deformability. Decrease in erythrocyte zinc level may have caused the impairment in erythrocyte deformability.

  4. The Effects of Electromagnetic Fields Generated from 1800 MHz Cell Phones on Erythrocyte Rheological Parameters and Zinc Level in Rats.

    Science.gov (United States)

    Erken, Gülten; Küçükatay, Melek Bor; Turgut, Sebahat; Erken, Haydar Ali; Cömlekçi, Selçuk; Divrikli, Umit; Genç, Osman

    2012-06-01

    The aim of this study was to investigate the effects of the electromagnetic field generated from the 1800 MHz radiofrequency radiation (EF) on erythrocyte rheological parameters and erythrocyte zinc levels. Twenty-four male Wistar Albino rats were randomly grouped as follows: 1) two control groups and 2) study groups: i) Group A: EF exposed group (2.5 h/day for 30 days, the phone on stand-by), and ii) Group B: EF exposed group (2.5 min/day for 30 days, the phone ringing in silent mode). At the end of the experimental period erythrocyte rheological parameters such as erythrocyte deformability and aggregation were determined by an ectacytometer. Erythrocyte zinc level, which affects hemorheological parameters, was also measured by atomic absorption spectrophotometer. Erythrocyte deformability was decreased in both study groups but the decrease in group A was not statistically significant. Exposure to EF did not have any significant effect on erythrocyte aggregation. On the other hand, erythrocyte zinc level was significantly reduced in both study groups. Exposure to EF may have decreased tissue oxygenation due to reduced erythrocyte deformability. Decrease in erythrocyte zinc level may have caused the impairment in erythrocyte deformability.

  5. Arteriolar oxygen reactivity: where is the sensor and what is the mechanism of action?

    Science.gov (United States)

    2016-01-01

    Abstract Arterioles in the peripheral microcirculation are exquisitely sensitive to changes in PO2 in their environment: increases in PO2 cause vasoconstriction while decreases in PO2 result in vasodilatation. However, the cell type that senses O2 (the O2 sensor) and the signalling pathway that couples changes in PO2 to changes in arteriolar tone (the mechanism of action) remain unclear. Many (but not all) ex vivo studies of isolated cannulated resistance arteries and large, first‐order arterioles support the hypothesis that these vessels are intrinsically sensitive to PO2 with the smooth muscle, endothelial cells, or red blood cells serving as the O2 sensor. However, in situ studies testing these hypotheses in downstream arterioles have failed to find evidence of intrinsic O2 sensitivity, and instead have supported the idea that extravascular cells sense O2. Similarly, ex vivo studies of isolated, cannulated resistance arteries and large first‐order arterioles support the hypotheses that O2‐dependent inhibition of production of vasodilator cyclooxygenase products or O2‐dependent destruction of nitric oxide mediates O2 reactivity of these upstream vessels. In contrast, most in vivo studies of downstream arterioles have disproved these hypotheses and instead have provided evidence supporting the idea that O2‐dependent production of vasoconstrictors mediates arteriolar O2 reactivity, with significant regional heterogeneity in the specific vasoconstrictor involved. Oxygen‐induced vasoconstriction may serve as a protective mechanism to reduce the oxidative burden to which a tissue is exposed, a process that is superimposed on top of the local mechanisms which regulate tissue blood flow to meet a tissue's metabolic demand. PMID:27324312

  6. Magnetic particles-based biosensor for biogenic amines using an optical oxygen sensor as a transducer

    International Nuclear Information System (INIS)

    Pospiskova, K.; Sebela, M.; Safarik, I.; Kuncova, G.

    2013-01-01

    We have developed a fibre optic biosensor with incorporated magnetic microparticles for the determination of biogenic amines. The enzyme diamine oxidase from Pisum sativum was immobilized either on chitosan-coated magnetic microparticles or on commercial microbeads modified with a ferrofluid. Both the immobilized enzyme and the ruthenium complex were incorporated into a UV-cured inorganic-organic polymer composite and deposited on a lens that was connected, by optical fibres, to an electro-optical detector. The enzyme catalyzes the oxidation of amines under consumption of oxygen. The latter was determined by measuring the quenched fluorescence lifetime of the ruthenium complex. The limits of detection for the biogenic amines putrescine and cadaverine are 25-30 μmol L -1 , and responses are linear up to a concentration of 1 mmol L -1 . (author)

  7. [Ceruloplasmin receptor on human erythrocytes].

    Science.gov (United States)

    Saenko, E L; Basevich, V V; Iaropolov, A I

    1988-08-01

    The structural fragments of the human ceruloplasmin (CP) molecule and of erythrocyte receptors which provide for the specific interaction of CP with erythrocytes were identified, and their properties were investigated. The interaction of CP with erythrocytes, both intact and treated with neuroaminidase and proteolytic enzymes (trypsin, chymotrypsin, papaine, pronase E) is described. Experiments with CP reception were performed at 4 degrees C, using [125I]CP and [125I]asialo-CP. The parameters of binding were determined in Scatchard plots. It was demonstrated that the specific binding of CP to erythrocyte receptors is determined by its interaction with two structural sites of the carbohydrate moiety of the CP molecule, i.e., the terminal residues of sialic acids and a site, (formula; see text) located at a large distance from the chain terminus.

  8. Accuracy of different sensors for the estimation of pollutant concentrations (total suspended solids, total and dissolved chemical oxygen demand) in wastewater and stormwater.

    Science.gov (United States)

    Lepot, Mathieu; Aubin, Jean-Baptiste; Bertrand-Krajewski, Jean-Luc

    2013-01-01

    Many field investigations have used continuous sensors (turbidimeters and/or ultraviolet (UV)-visible spectrophotometers) to estimate with a short time step pollutant concentrations in sewer systems. Few, if any, publications compare the performance of various sensors for the same set of samples. Different surrogate sensors (turbidity sensors, UV-visible spectrophotometer, pH meter, conductivity meter and microwave sensor) were tested to link concentrations of total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), and sensors' outputs. In the combined sewer at the inlet of a wastewater treatment plant, 94 samples were collected during dry weather, 44 samples were collected during wet weather, and 165 samples were collected under both dry and wet weather conditions. From these samples, triplicate standard laboratory analyses were performed and corresponding sensors outputs were recorded. Two outlier detection methods were developed, based, respectively, on the Mahalanobis and Euclidean distances. Several hundred regression models were tested, and the best ones (according to the root mean square error criterion) are presented in order of decreasing performance. No sensor appears as the best one for all three investigated pollutants.

  9. ZrO2 oxygen and hydrogen sensors: A geologic perspective

    International Nuclear Information System (INIS)

    Ulmer, G.C.

    1983-01-01

    The geosciences have been attracted to the high accuracy of 5 ZrO 2 cells for both f(O 2 ) and pH sensors. That the very same ZrO 2 membrane can be used above 600 0 C to sense f(O 2 ) and used between 25 0 and 300 0 C (maybe higher) to sense pH has been demonstrated. Specific resistivity measurements for such cells follow the equation log R = -2.20 + 4000/T (for T(K) from 298-1573 K) (for Y 2 O 3 levels of 4-8 mol%). In the lower-temperature regime, i.e., pH sensing, the ZrO 2 cell does not respond to changes in molecular O 2 or H 2 in its environment. Geochemical raw material impurities and ZrO 2 membrane fabrication techniques that affect f(O 2 ) and pH sensing are discussed. The application of ZrO 2 cells to various geologic redox equilibria are demonstrated by a few selected examples

  10. Design and Characterization of a Sensorized Microfluidic Cell-Culture System with Electro-Thermal Micro-Pumps and Sensors for Cell Adhesion, Oxygen, and pH on a Glass Chip

    Directory of Open Access Journals (Sweden)

    Sebastian M. Bonk

    2015-07-01

    Full Text Available We combined a multi-sensor glass-chip with a microfluidic channel grid for the characterization of cellular behavior. The grid was imprinted in poly-dimethyl-siloxane. Mouse-embryonal/fetal calvaria fibroblasts (MC3T3-E1 were used as a model system. Thin-film platinum (Pt sensors for respiration (amperometric oxygen electrode, acidification (potentiometric pH electrodes and cell adhesion (interdigitated-electrodes structures, IDES allowed us to monitor cell-physiological parameters as well as the cell-spreading behavior. Two on-chip electro-thermal micro-pumps (ETμPs permitted the induction of medium flow in the system, e.g., for medium mixing and drug delivery. The glass-wafer technology ensured the microscopic observability of the on-chip cell culture. Connecting Pt structures were passivated by a 1.2 μm layer of silicon nitride (Si3N4. Thin Si3N4 layers (20 nm or 60 nm were used as the sensitive material of the pH electrodes. These electrodes showed a linear behavior in the pH range from 4 to 9, with a sensitivity of up to 39 mV per pH step. The oxygen sensors were circular Pt electrodes with a sensor area of 78.5 μm2. Their sensitivity was 100 pA per 1% oxygen increase in the range from 0% to 21% oxygen (air saturated. Two different IDES geometries with 30- and 50-μm finger spacings showed comparable sensitivities in detecting the proliferation rate of MC3T3 cells. These cells were cultured for 11 days in vitro to test the biocompatibility, microfluidics and electric sensors of our system under standard laboratory conditions.

  11. Factors affecting the performance of a single-chamber microbial fuel cell-type biological oxygen demand sensor.

    Science.gov (United States)

    Yang, Gai-Xiu; Sun, Yong-Ming; Kong, Xiao-Ying; Zhen, Feng; Li, Ying; Li, Lian-Hua; Lei, Ting-Zhou; Yuan, Zhen-Hong; Chen, Guan-Yi

    2013-01-01

    Microbial fuel cells (MFCs) are devices that exploit microorganisms as biocatalysts to degrade organic matter or sludge present in wastewater (WW), and thereby generate electricity. We developed a simple, low-cost single-chamber microbial fuel cell (SCMFC)-type biochemical oxygen demand (BOD) sensor using carbon felt (anode) and activated sludge, and demonstrated its feasibility in the construction of a real-time BOD measurement system. Further, the effects of anodic pH and organic concentration on SCMFC performance were examined, and the correlation between BOD concentration and its response time was analyzed. Our results demonstrated that the SCMFC exhibited a stable voltage after 132 min following the addition of synthetic WW (BOD concentration: 200 mg/L). Notably, the response signal increased with an increase in BOD concentration (range: 5-200 mg/L) and was found to be directly proportional to the substrate concentration. However, at higher BOD concentrations (>120 mg/L) the response signal remained unaltered. Furthermore, we optimized the SCMFC using synthetic WW, and tested it with real WW. Upon feeding real WW, the BOD values exhibited a standard deviation from 2.08 to 8.3% when compared to the standard BOD5 method, thus demonstrating the practical applicability of the developed system to real treatment effluents.

  12. Quantitative evaluation of respiration induced metabolic oscillations in erythrocytes

    DEFF Research Database (Denmark)

    Hald, Bjørn; Madsen, Mads F; Danø, Sune

    2009-01-01

    The changes in the partial pressures of oxygen and carbon dioxide (P(O(2)) and P(CO(2))) during blood circulation alter erythrocyte metabolism, hereby causing flux changes between oxygenated and deoxygenated blood. In the study we have modeled this effect by extending the comprehensive kinetic...... model by Mulquiney and Kuchel [P.J. Mulquiney, and P.W. Kuchel. Model of 2,3-bisphosphoglycerate metabolism in the human erythrocyte based on detailed enzyme kinetic equations: equations and parameter refinement, Biochem. J. 1999, 342, 581-596.] with a kinetic model of hemoglobin oxy...... solely by steady state consideration. The metabolic system exhibits a broad distribution of time scales. Relaxations of modes with hemoglobin and Mg(2+) binding reactions are very fast, while modes involving glycolytic, membrane transport and 2,3-BPG shunt reactions are much slower. Incomplete slow mode...

  13. Erythrocyte fluorescence and lead intoxication.

    Science.gov (United States)

    Clark, K G

    1976-01-01

    Blood samples from people exposed to inorganic lead were examined by fluorescence microscopy for excess erythrocyte porphyrin. With continued lead absorption, fluorescent erythrocytes appeared in the circulation of workers handling this metal or its compounds, and they progressively increased in number and brilliance. These changes ensued if the blood lead concentration was maintained above 2-42 mumol/l (50 mug/100 ml), and preceded any material fall in the haemoglobin value. At one factory, 62-5% of 81 symptomless workers showed erythrocyte fluorescence attributable to the toxic effects of lead. Excess fluorocytes were found in blood samples from a child with pica and three of her eight siblings. These four were subsequently shown to have slightly increased blood lead concentrations (2-03 to 2-32 mumol/l). Fluorescence microscopy for excess erythrocyte porphyrin is a sensitive method for the detection of chronic lead intoxication. A relatively slight increase in the blood lead is associated with demonstrabel changes in erythrocyte porphyrin content. The procedure requires little blood, and may be performed upon stored samples collected for lead estimation. The results are not readily influenced by contamination, and provide good confirmatory evidence for the absorption of biochemically active lead. PMID:963005

  14. Amperometric NOx-sensor for Combustion Exhaust Gas Control. Studies on transport properties and catalytic activity of oxygen permeable ceramic membranes

    International Nuclear Information System (INIS)

    Romer, E.W.J.

    2001-01-01

    The aim of the research described in this thesis is the development of a mixed conducting oxide layer, which can be used as an oxygen permselective membrane in an amperometric NOx sensor. The sensor will be used in exhaust gas systems. The exhaust gas-producing engine will run in the lean mix mode. The preparation of this sensor is carried out using screen-printing technology, in which the different layers of the sensor are applied successively. Hereafter, a co-firing step is applied in which all layers are sintered together. This co-firing step imposes several demands on the selection of materials. The design specifications of the sensor further include requirements concerning the operating temperature, measurement range and overall stability. The operating temperature of the sensor varies between 700 and 850C, enabling measurement of NOx concentrations between 50 and 1200 ppm with a measurement accuracy of 10 ppm. Concerning the stability of the sensor, it must withstand the exhaust gas atmosphere containing, amongst others, smoke, acids, abrasive particles and sulphur. Because of the chosen lean-mix engine concept, in which the fuel/air mixture switches continuously between lean (excess oxygen) and fat (excess fuel) mixtures, the sensor must withstand alternately oxidising and reducing atmospheres. Besides, it should be resistant to thermal shock and show no cross-sensitivity of NOx with other exhaust gas constituents like oxygen and hydrocarbons. The response time should be short, typically less than 500 ms. Because of the application in combustion engines of cars, the operational lifetime should be longer than 10 years. Demands on the mixed conducting oxide layer include the following ones. The layer should show minimal catalytic activity towards NOx-reduction. The oxygen permeability must be larger than 6.22 10 -8 mol/cm 2 s at a layer thickness between 3-50 μm. Since the mixed conducting oxide layer is coated on the YSZ electrolyte embodiment, the two

  15. Long-term performance of Aanderaa optodes and sea-bird SBE-43 dissolved-oxygen sensors bottom mounted at 32 m in Massachusetts Bay

    Science.gov (United States)

    Martini, Marinna A.; Butman, Bradford; Mickelson, Michael J.

    2007-01-01

    A field evaluation of two new dissolved-oxygen sensing technologies, the Aanderaa Instruments AS optode model 3830 and the Sea-Bird Electronics, Inc., model SBE43, was carried out at about 32-m water depth in western Massachusetts Bay. The optode is an optical sensor that measures fluorescence quenching by oxygen molecules, while the SBE43 is a Clark polarographic membrane sensor. Optodes were continuously deployed on bottom tripod frames by exchanging sensors every 4 months over a 19-month period. A Sea-Bird SBE43 was added during one 4-month deployment. These moored observations compared well with oxygen measurements from profiles collected during monthly shipboard surveys conducted by the Massachusetts Water Resources Authority. The mean correlation coefficient between the moored measurements and shipboard survey data was >0.9, the mean difference was 0.06 mL L−1, and the standard deviation of the difference was 0.15 mL L−1. The correlation coefficient between the optode and the SBE43 was >0.9 and the mean difference was 0.07 mL L−1. Optode measurements degraded when fouling was severe enough to block oxygen molecules from entering the sensing foil over a significant portion of the sensing window. Drift observed in two optodes beginning at about 225 and 390 days of deployment is attributed to degradation of the sensing foil. Flushing is necessary to equilibrate the Sea-Bird sensor. Power consumption by the SBE43 and required pump was 19.2 mWh per sample, and the optode consumed 0.9 mWh per sample, both within expected values based on manufacturers’ specifications.

  16. Factors influencing erythrocyte choline concentrations.

    Science.gov (United States)

    Miller, B L; Jenden, D J; Tang, C; Read, S

    1989-01-01

    Choline concentrations in human erythrocytes increase after freezing and thawing, during incubation in Krebs-phosphate for 30 min or on storage at 0 degrees C for 3-24 hr. The increase is prevented by protein precipitation by 10% perchloric acid, 10% zinc hydroxide, 10% sodium tungstate or boiling in water. It is not prevented by EDTA (10 mM) and is increased by oleate (5 mM). We suggest that the increase is due to the action of phospholipase D on erythrocyte phospholipids.

  17. Inkjet printing of nanoporous gold electrode arrays on cellulose membranes for high-sensitive paper-like electrochemical oxygen sensors using ionic liquid electrolytes.

    Science.gov (United States)

    Hu, Chengguo; Bai, Xiaoyun; Wang, Yingkai; Jin, Wei; Zhang, Xuan; Hu, Shengshui

    2012-04-17

    A simple approach to the mass production of nanoporous gold electrode arrays on cellulose membranes for electrochemical sensing of oxygen using ionic liquid (IL) electrolytes was established. The approach, combining the inkjet printing of gold nanoparticle (GNP) patterns with the self-catalytic growth of these patterns into conducting layers, can fabricate hundreds of self-designed gold arrays on cellulose membranes within several hours using an inexpensive inkjet printer. The resulting paper-based gold electrode arrays (PGEAs) had several unique properties as thin-film sensor platforms, including good conductivity, excellent flexibility, high integration, and low cost. The porous nature of PGEAs also allowed the addition of electrolytes from the back cellulose membrane side and controllably produced large three-phase electrolyte/electrode/gas interfaces at the front electrode side. A novel paper-based solid-state electrochemical oxygen (O(2)) sensor was therefore developed using an IL electrolyte, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). The sensor looked like a piece of paper but possessed high sensitivity for O(2) in a linear range from 0.054 to 0.177 v/v %, along with a low detection limit of 0.0075% and a short response time of less than 10 s, foreseeing its promising applications in developing cost-effective and environment-friendly paper-based electrochemical gas sensors.

  18. Changes in haematology, plasma biochemistry and erythrocyte ...

    African Journals Online (AJOL)

    The results suggest that maintaining wild birds in captivity for a prolonged period could be stressful as shown by the heterophil/lymphocytes ratio and reduced erythrocyte osmotic resistance, and could lead to decreases in erythrocyte parameters and muscle wasting. Keywords: Haematological parameters, erythrocyte ...

  19. Minimizing the effects of oxygen interference on l-lactate sensors by a single amino acid mutation in Aerococcus viridansl-lactate oxidase.

    Science.gov (United States)

    Hiraka, Kentaro; Kojima, Katsuhiro; Lin, Chi-En; Tsugawa, Wakako; Asano, Ryutaro; La Belle, Jeffrey T; Sode, Koji

    2018-04-30

    l-lactate biosensors employing l-lactate oxidase (LOx) have been developed mainly to measure l-lactate concentration for clinical diagnostics, sports medicine, and the food industry. Some l-lactate biosensors employ artificial electron mediators, but these can negatively impact the detection of l-lactate by competing with the primary electron acceptor: molecular oxygen. In this paper, a strategic approach to engineering an AvLOx that minimizes the effects of oxygen interference on sensor strips was reported. First, we predicted an oxygen access pathway in Aerococcus viridans LOx (AvLOx) based on its crystal structure. This was subsequently blocked by a bulky amino acid substitution. The resulting Ala96Leu mutant showed a drastic reduction in oxidase activity using molecular oxygen as the electron acceptor and a small increase in dehydrogenase activity employing an artificial electron acceptor. Secondly, the Ala96Leu mutant was immobilized on a screen-printed carbon electrode using glutaraldehyde cross-linking method. Amperometric analysis was performed with potassium ferricyanide as an electron mediator under argon or atmospheric conditions. Under argon condition, the response current increased linearly from 0.05 to 0.5mM l-lactate for both wild-type and Ala96Leu. However, under atmospheric conditions, the response of wild-type AvLOx electrode was suppressed by 9-12% due to oxygen interference. The Ala96Leu mutant maintained 56-69% of the response current at the same l-lactate level and minimized the relative bias error to -19% from -49% of wild-type. This study provided significant insight into the enzymatic reaction mechanism of AvLOx and presented a novel approach to minimize oxygen interference in sensor applications, which will enable accurate detection of l-lactate concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Sensor

    OpenAIRE

    Gleeson, Helen; Dierking, Ingo; Grieve, Bruce; Woodyatt, Christopher; Brimicombe, Paul

    2015-01-01

    An electrical temperature sensor (10) comprises a liquid crystalline material (12). First and second electrically conductive contacts (14), (16), having a spaced relationship there between, contact the liquid crystalline material (12). An electric property measuring device is electrically connected to the first and second contacts (14), (16) and is arranged to measure an electric property of the liquid crystalline material (12). The liquid crystalline material (12) has a transition temperatur...

  1. Borderline maintenance of erythrocyte 2,3-diphosphoglycerate concentrations in normoxic type 1 (insulin dependent) diabetic subjects.

    Science.gov (United States)

    Story, C J; Roberts, A P; Ryall, R G

    1986-02-01

    Erythrocyte 2,3-diphosphoglycerate and haemoglobin A1c concentrations were measured in 26 clinically normoxic patients with type 1 (insulin dependent) diabetes mellitus. The concentration of 2,3-diphosphoglycerate theoretically required to maintain normal erythrocyte oxygen delivery function in each subject was calculated and compared with the measured concentrations. In the majority of diabetic patients 2,3-diphosphoglycerate concentrations were sufficient to keep the erythrocyte oxygen dissociation curve within the normal range under otherwise normal blood conditions. There was, however, a minority of patients in which this was not true. It is concluded that the increased erythrocyte 2,3-diphosphoglycerate concentrations in clinically normoxic diabetic subjects are generally less than compensatory for the effect of haemoglobin A1c formation on the haemoglobin-oxygen dissociation curve.

  2. Influence of Erythrocyte Membrane Stability in Atherosclerosis.

    Science.gov (United States)

    da Silva Garrote-Filho, Mario; Bernardino-Neto, Morun; Penha-Silva, Nilson

    2017-04-01

    The purpose of this study is to show how an excess of cholesterol in the erythrocyte membrane contributes stochastically to the progression of atherosclerosis, leading to damage in blood rheology and O 2 transport, deposition of cholesterol (from trapped erythrocytes) in an area of intraplaque hemorrhage, and local exacerbation of oxidative stress. Cholesterol contained in the membrane of erythrocytes trapped in an intraplaque hemorrhage contributes to the growth of the necrotic nucleus. There is even a relationship between the amount of cholesterol in the erythrocyte membrane and the severity of atherosclerosis. In addition, the volume variability among erythrocytes, measured by RDW, is predictive of a worsening of this disease. Erythrocytes contribute to the development of atherosclerosis in several ways, especially when trapped in intraplate hemorrhage. These erythrocytes are oxidized and phagocytosed by macrophages. The cholesterol present in the membrane of these erythrocytes subsequently contributes to the growth of the atheroma plaque. In addition, when they rupture, erythrocytes release hemoglobin, which leads to the generation of free radicals. Finally, increased RDW may predict the worsening of atherosclerosis, due to the effects of inflammation and oxidative stress on erythropoiesis and erythrocyte volume. A better understanding of erythrocyte participation in atherosclerosis may contribute to the improvement of the prevention and treatment strategies of this disease.

  3. Hot spot in GdBa2Cu3O7-δ-based composite ceramics rods and their applications for oxygen sensors

    International Nuclear Information System (INIS)

    Okamoto, T; Takata, M

    2011-01-01

    A hot spot, which is a local area glowing orange, appears in a LnBa 2 Cu 3 O 7-δ (Ln: rare earth element) ceramic rod when a voltage exceeding a certain value is applied to the rod at room temperature. After the appearance of the hot spot, the current changes according to the oxygen partial pressure in ambient atmosphere, which acts as an oxygen sensor without the need for any heating system. The GdBa 2 Cu 3 O 7-δ rod tended to be melted and broken by a sustained presence of the hot spot in a high oxygen partial pressure Po 2 (∼100 kPa). The composite rod containing high melting point materials, such as BaAl 2 O 4 , BaZrO 3 and Gd 2 BaCuO 5 , showed a remarkable high durability in O 2 atmosphere. In a low Po 2 ( 2 Cu3O 7-δ rod decreases to almost zero and the hot spot disappeared, resulting in an insensitive rod to oxygen. The composite rod containing CuO detected oxygen even in Po 2 < 0.002 kPa.

  4. Dissolved Oxygen Sensor in Animal-Borne Instruments: An Innovation for Monitoring the Health of Oceans and Investigating the Functioning of Marine Ecosystems.

    Science.gov (United States)

    Bailleul, Frederic; Vacquie-Garcia, Jade; Guinet, Christophe

    2015-01-01

    The current decline in dissolved oxygen concentration within the oceans is a sensitive indicator of the effect of climate change on marine environment. However the impact of its declining on marine life and ecosystems' health is still quite unclear because of the difficulty in obtaining in situ data, especially in remote areas, like the Southern Ocean (SO). Southern elephant seals (Mirounga leonina) proved to be a relevant alternative to the traditional oceanographic platforms to measure physical and biogeochemical structure of oceanic regions rarely observed. In this study, we use a new stage of development in biologging technology to draw a picture of dissolved oxygen concentration in the SO. We present the first results obtained from a dissolved oxygen sensor added to Argos CTD-SRDL tags and deployed on 5 female elephant seals at Kerguelen. From October 2010 and October 2011, 742 oxygen profiles associated with temperature and salinity measurements were recorded. Whether a part of the data must be considered cautiously, especially because of offsets and temporal drifts of the sensors, the range of values recorded was consistent with a concomitant survey conducted from a research vessel (Keops-2 project). Once again, elephant seals reinforced the relationship between marine ecology and oceanography, delivering essential information about the water masses properties and the biological status of the Southern Ocean. But more than the presentation of a new stage of development in animal-borne instrumentation, this pilot study opens a new field of investigation in marine ecology and could be enlarged in a near future to other key marine predators, especially large fish species like swordfish, tuna or sharks, for which dissolved oxygen is expected to play a crucial role in distribution and behaviour.

  5. Dissolved Oxygen Sensor in Animal-Borne Instruments: An Innovation for Monitoring the Health of Oceans and Investigating the Functioning of Marine Ecosystems.

    Directory of Open Access Journals (Sweden)

    Frederic Bailleul

    Full Text Available The current decline in dissolved oxygen concentration within the oceans is a sensitive indicator of the effect of climate change on marine environment. However the impact of its declining on marine life and ecosystems' health is still quite unclear because of the difficulty in obtaining in situ data, especially in remote areas, like the Southern Ocean (SO. Southern elephant seals (Mirounga leonina proved to be a relevant alternative to the traditional oceanographic platforms to measure physical and biogeochemical structure of oceanic regions rarely observed. In this study, we use a new stage of development in biologging technology to draw a picture of dissolved oxygen concentration in the SO. We present the first results obtained from a dissolved oxygen sensor added to Argos CTD-SRDL tags and deployed on 5 female elephant seals at Kerguelen. From October 2010 and October 2011, 742 oxygen profiles associated with temperature and salinity measurements were recorded. Whether a part of the data must be considered cautiously, especially because of offsets and temporal drifts of the sensors, the range of values recorded was consistent with a concomitant survey conducted from a research vessel (Keops-2 project. Once again, elephant seals reinforced the relationship between marine ecology and oceanography, delivering essential information about the water masses properties and the biological status of the Southern Ocean. But more than the presentation of a new stage of development in animal-borne instrumentation, this pilot study opens a new field of investigation in marine ecology and could be enlarged in a near future to other key marine predators, especially large fish species like swordfish, tuna or sharks, for which dissolved oxygen is expected to play a crucial role in distribution and behaviour.

  6. 51Cr - erythrocyte survival curves

    International Nuclear Information System (INIS)

    Paiva Costa, J. de.

    1982-07-01

    Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt

  7. Study and development of a fluorescence based sensor system for monitoring oxygen in wine production : the WOW project

    NARCIS (Netherlands)

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghesso, Gaudenzio; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe; Cenedese, Angelo

    2018-01-01

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of

  8. Influence of zirconium doping in ceria lattice as an active electrode in amperometric electrochemical ammonia gas sensor using oxygen pumping current

    International Nuclear Information System (INIS)

    Sharan, R.; Dutta, Atanu; Roy, Mainak

    2016-01-01

    An amperometric electrochemical sensor using Ce-Zr system as ammonia gas detecting electrode is reported. Using lanthanum gallate based electrolyte La_0_._8Sr_0_._2Ga_0_._8Mg_0_._1Ni_0_._1O_3 (LSGMN) and lanthanum strontium cobaltite La_0_._5Sr_0_._5CoO_3 (LSC) as oxygen reduction electrode, the sensor was found to be highly sensitive to NH_3 gas down to few ppm level, when operated in the temperature range 300-450°C. Keeping LSC electrodecomposition same, when sensing properties were studied with the variation of Zr concentration in ceria for active electrode, sensor with 30 mol % Zr doped ceria showed highest sensitivity of 28μA/ decade at 400°C. For all active electrodecompositions Ce_1_-_xZr_xO_2 (x = 0 to 0.7) highest sensitivity was observed at 400°C. All the sensors performed reproducibly with time response and recovery time 40 and 120 seconds respectively. (author)

  9. The first case of a complete deficiency of diphosphoglycerate mutase in human erythrocytes.

    Science.gov (United States)

    Rosa, R; Prehu, M O; Beuzard, Y; Rosa, J

    1978-01-01

    An inherited and complete deficiency of diphosphoglycerate mutase was discovered in the erythrocytes of a 42-yr-old man of French origin whose blood hemoglobin concentration was 19.0 g/dl. Upon physical examination he was normal with the exception of a ruddy cyanosis. The morphology of his erythrocytes was also normal and there was no evidence of hemolysis. The erythrocyte 2,3-diphosphoglycerate level was below 3% of normal values and, as a consequence, the affinity of the cells for oxygen was increased. Diphosphoglycerate mutase activity was undetectable in erythrocytes as was that of diphosphoglycerate phosphatase. The activities of all the other erythrocyte enzymes that were tested were normal except for nomophosphoglycerate mutase which was diminished to 50% of the normal value. The levels of reduced glutathione, ATP, fructose 1,6-diphosphate, and of triose phosphates were elevated, whereas those of glucose 6-phosphate and fructose 6-phosphate were decreased. This report sheds new light on the role of diphosphoglycerate mutase in the metabolism of erythrocytes. Images PMID:152321

  10. The first case of a complete deficiency of diphosphoglycerate mutase in human erythrocytes.

    Science.gov (United States)

    Rosa, R; Prehu, M O; Beuzard, Y; Rosa, J

    1978-11-01

    An inherited and complete deficiency of diphosphoglycerate mutase was discovered in the erythrocytes of a 42-yr-old man of French origin whose blood hemoglobin concentration was 19.0 g/dl. Upon physical examination he was normal with the exception of a ruddy cyanosis. The morphology of his erythrocytes was also normal and there was no evidence of hemolysis. The erythrocyte 2,3-diphosphoglycerate level was below 3% of normal values and, as a consequence, the affinity of the cells for oxygen was increased. Diphosphoglycerate mutase activity was undetectable in erythrocytes as was that of diphosphoglycerate phosphatase. The activities of all the other erythrocyte enzymes that were tested were normal except for nomophosphoglycerate mutase which was diminished to 50% of the normal value. The levels of reduced glutathione, ATP, fructose 1,6-diphosphate, and of triose phosphates were elevated, whereas those of glucose 6-phosphate and fructose 6-phosphate were decreased. This report sheds new light on the role of diphosphoglycerate mutase in the metabolism of erythrocytes.

  11. Carbon dioxide transport in alligator blood and its erythrocyte permeability to anions and water

    DEFF Research Database (Denmark)

    Jensen, F B; Wang, T; Jones, D R

    1998-01-01

    Deoxygenation of alligator red blood cells (RBCs) caused binding of two HCO3- equivalents per hemoglobin (Hb) tetramer at physiological pH. At lowered pH, some HCO3- binding also occurred to oxygenated Hb. The erythrocytic total CO2 content was large, and Hb-bound HCO3-, free HCO3-, and carbamate...

  12. Erythrocytes in alternating electric fields

    International Nuclear Information System (INIS)

    Morariu, V.V.; Chifu, A.; Simplaceanu, T.; Frangopol, P.T.

    1983-02-01

    The elastic and inelastic deformation of erythrocytes induced by alternating fields and the suggestion that moderate field intensities (1.2 kV/cm) when continuously applied can cause lysis by a different mechanism compared to the action of short intense field pulses is presented. The different experimental conditions can be used to approach various properties of the membrane such as those related to the dielectric polarization of the membrane or to the interfacial polarization, leading to the inelastic deformation of the cells. (authors)

  13.  Oxidative stress modulates the organization of erythrocyte membrane cytoskeleton

    Directory of Open Access Journals (Sweden)

    Maria Olszewska

    2012-07-01

    Full Text Available  Background:Apart from their main role in transporting oxygen and carbon dioxide, erythrocytes play also an important role in organism antioxidative defence. Direct exposure to reactive oxygen species (ROS results in shortening of their half-life, even by 50�20The presence of glucose, being the substrate in pentose phosphate pathway (PPP cycle, is one of the factors that can have influence on the level of oxidative stress. The activity of PPP increases during oxidative stress. Glucose guarantees normal PPP functioning with the production of reductive equivalents in the amounts necessary to reproduction of glutathione – nonenzymatic free radical scavenger. In available literature there are no reports regarding the changes in protein contents of erythrocyte cytoskeleton exposed to t-butyl hydroperoxide in relation to glucose presence in incubation medium.Material/methods:Erythrocytes taken from 10 healthy subjects were used to assess the influence of generated free radicals on erythrocyte proteins and chosen parameters of oxidative stress. Erythrocytes were incubated in the solutions containing deferent concentrations of t-butyl hydroperoxide and glucose. Electrophoresis was performed on polyacrylamide gel in denaturating conditions. The contents of tryptophan in membranes was evaluated spectrofluorometrically.Results/conclusions:In vitro conditions oxidative stress leads to protein damage in erythrocyte cytoskeleton, both in proteins inside the cell as well as having contact with extracellular environment. In consequence, the amount of low-molecular proteins – mainly globin, which bind to cytoskeleton, increases. This process takes place independently of glucose presence in incubation medium. One of the element of protein cytoskeleton, tryptophan, also undergoes degradation. The decrease of its contents is higher during erythrocyte exposure to t-BOOH in environment containing glucose, what can suggest prooxidative influence of glucose in

  14. Quinones: reactions with hemoglobin, effects within erythrocytes and potential for antimalarial development

    International Nuclear Information System (INIS)

    Denny, B.J.

    1986-01-01

    The focus of this research was to characterize the interactions of some simple quinone like compounds with purified hemoglobin and to study the effects of these compounds within erythrocytes. It is proposed that these sorts of agents can have an antimalarial effect. The simplest compounds chosen for study were benzoquinone, methylquinone (toluquinone) and hydroquinone. When 14 C-quinone was reacted with purified hemoglobin (Hb) there was rapid binding of the first two moles of substrate per Hb molecule. An unusual property of the modified Hb's is that in the presence of a redox sensitive agent such as cytochrome c they are capable of generating superoxide anions. Within erythrocytes, quinone and toluquinone which differ only by a single methyl group have completely different effects. Toluquinone causes the cells to hemolyse and the effect was enhanced when the erythrocyte superoxide dismutase was inhibited; the effect was diminished when scavengers of activated oxygen such as histidine, mannitol and vital E were present. Benzoquinone on the other hand did not cause the cells to hemolyse and instead appeared to protect the cells from certain hemolytic stresses. Growth of malaria parasites in erythrocytes has been shown to be inhibited by activated forms of oxygen, also some quinone like agents in the past have been shown to inhibit the parasite's metabolism. An initial experiment with erythrocytes infected with malaria parasites showed that quinone and toluquinone could both inhibit the growth rate of parasites

  15. DELETION OR INHIBITION OF THE OXYGEN SENSOR PHD1 PROTECTS AGAINST ISCHEMIC STROKE VIA REPROGRAMMING OF NEURONAL METABOLISM

    Science.gov (United States)

    Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Schoors, Sandra; Janaki Raman, Sudha Rani; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S.; Hung, Gene; Bossaert, Goele; Cleveland, Don W.; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C. Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Fendt, Sarah-Maria; Ghesquière, Bart; Carmeliet, Peter

    2016-01-01

    Summary The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network, nor to enhanced neurotrophin expression. Instead, PHD1−/− neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1−/− neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose from glycolysis. As a result, PHD1−/− neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a novel regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. PMID:26774962

  16. Deletion or Inhibition of the Oxygen Sensor PHD1 Protects against Ischemic Stroke via Reprogramming of Neuronal Metabolism.

    Science.gov (United States)

    Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Davidson, Shawn M; Schoors, Sandra; Broekaert, Dorien; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S; Hung, Gene; Bossaert, Goele; Cleveland, Don W; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Ghesquière, Bart; Fendt, Sarah-Maria; Carmeliet, Peter

    2016-02-09

    The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network. Instead, PHD1(-/-) neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1(-/-) neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose away from glycolysis. As a result, PHD1(-/-) neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Hypoxia-dependent sequestration of an oxygen sensor by a widespread structural motif can shape the hypoxic response - a predictive kinetic model

    Directory of Open Access Journals (Sweden)

    Novák Béla

    2010-10-01

    Full Text Available Abstract Background The activity of the heterodimeric transcription factor hypoxia inducible factor (HIF is regulated by the post-translational, oxygen-dependent hydroxylation of its α-subunit by members of the prolyl hydroxylase domain (PHD or EGLN-family and by factor inhibiting HIF (FIH. PHD-dependent hydroxylation targets HIFα for rapid proteasomal degradation; FIH-catalysed asparaginyl-hydroxylation of the C-terminal transactivation domain (CAD of HIFα suppresses the CAD-dependent subset of the extensive transcriptional responses induced by HIF. FIH can also hydroxylate ankyrin-repeat domain (ARD proteins, a large group of proteins which are functionally unrelated but share common structural features. Competition by ARD proteins for FIH is hypothesised to affect FIH activity towards HIFα; however the extent of this competition and its effect on the HIF-dependent hypoxic response are unknown. Results To analyse if and in which way the FIH/ARD protein interaction affects HIF-activity, we created a rate equation model. Our model predicts that an oxygen-regulated sequestration of FIH by ARD proteins significantly shapes the input/output characteristics of the HIF system. The FIH/ARD protein interaction is predicted to create an oxygen threshold for HIFα CAD-hydroxylation and to significantly sharpen the signal/response curves, which not only focuses HIFα CAD-hydroxylation into a defined range of oxygen tensions, but also makes the response ultrasensitive to varying oxygen tensions. Our model further suggests that the hydroxylation status of the ARD protein pool can encode the strength and the duration of a hypoxic episode, which may allow cells to memorise these features for a certain time period after reoxygenation. Conclusions The FIH/ARD protein interaction has the potential to contribute to oxygen-range finding, can sensitise the response to changes in oxygen levels, and can provide a memory of the strength and the duration of a

  18. Triggering of Suicidal Erythrocyte Death Following Boswellic Acid Exposure

    Directory of Open Access Journals (Sweden)

    Salvatrice Calabrò

    2015-08-01

    Full Text Available Background/Aims: The antinflammatory natural product boswellic acid is effective against cancer at least in part by inducing tumor cell apoptosis. Similar to apoptosis of nucleated cells erythrocytes may enter eryptosis, a suicidal death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include oxidative stress, increase of cytosolic Ca2+-activity ([Ca2+]i, energy depletion, ceramide formation and p38 kinase activation. The present study tested, whether and how boswellic acid induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, ceramide abundance utilizing specific antibodies, reactive oxygen species (ROS from 2′,7′-dichlorodihydrofuorescein diacetate (DCFDA fluorescence, and cytosolic ATP concentration utilizing a luciferin-luciferase assay kit. Results: A 24 hours exposure of human erythrocytes to boswellic acid (5 µg/ml significantly increased the percentage of annexin-V-binding cells (to 9.3 ±0.9 % and significantly decreased forward scatter. Boswellic acid did not significantly modify [Ca2+]i, cytosolic ATP, ROS, or ceramide abundance. The effect of boswellic acid on annexin-V-binding was significantly blunted, but not abolished by p38 kinase inhibitors skepinone (2 µM and SB203580 (2 µM. Conclusions: Boswellic acid stimulates cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part dependent on p38 protein kinase activity.

  19. Luminescent Oxygen Gas Sensors Based on Nanometer-Thick Hybrid Films of Iridium Complexes and Clay Minerals

    Directory of Open Access Journals (Sweden)

    Hisako Sato

    2014-01-01

    Full Text Available The use of Ir(III complexes in photo-responsive molecular devices for oxygen gas sensing is reviewed. Attention is focused on the immobilization of Ir(III complexes in organic or inorganic host materials such as polymers, silica and clays in order to enhance robustness and reliability. Our recent works on constructing nanometer-thick films comprised of cyclometalated cationic Ir(III complexes and clay minerals are described. The achievement of multi-emitting properties in response to oxygen pressure is demonstrated.

  20. Tuning SERS for living erythrocytes

    DEFF Research Database (Denmark)

    Brazhe, Nadezda; Parshina, E.Y.; Khabanova, V.V.

    2013-01-01

    Surface-enhanced Raman spectroscopy (SERS) is a unique technique to study submembrane hemoglobin (Hbsm) in erythrocytes. We report the detailed design of SERS experiments on living erythrocytes to estimate dependence of the enhancemen t factor for main Raman bands of Hbsm on silver nanoparticle (Ag......NP) properties. We demonstrate that the enhancement factor for 4/A1g, 10/B1g and A2g Raman bands of Hbsm varies from 105 to 107 under proposed experimental conditions with 473 nm laser excitation. For the first time we show that the enhancement of Raman scattering increases with the increase in the relative...... between small AgNPs and Hbsm and, consequently, leads to the higher enhancement of Raman scattering of Hbsm. The enhancement of higher wavenumber bands 10/B1g and A2g is more sensitive to AgNPs' size and the relative amount of small AgNPs than the enhancement of the lower wavenumber band 4/A1g. This can...

  1. Invasion of erythrocytes by Babesia bovis

    NARCIS (Netherlands)

    Gaffar, Fasila Razzia

    2004-01-01

    In this thesis we investigated the invasion of erythrocytes taking place during the asexual erythrocytic blood stage of the apicomplexan parasites Babesia bovis parasite. Host cell invasion by apicomplexan parasites is a complex process requiring multiple receptor-ligand interactions, involving

  2. Enzymatic assay for methotrexate in erythrocytes

    DEFF Research Database (Denmark)

    Schrøder, H; Heinsvig, E M

    1985-01-01

    Methotrexate (MTX) accumulates in erythrocytes in MTX-treated patients. We present a modified enzymatic assay measuring MTX concentrations between 10 and 60 nmol/l in erythrocytes, adapted for a centrifugal analyser (Cobas Bio). About 40 patient's samples could be analysed within 1 h. The detection...

  3. Oxygen sensor nanoparticles for monitoring bacterial growth and characterization of dose–response functions in microfluidic screenings

    International Nuclear Information System (INIS)

    Cao, Jialan; Köhler, J. Michael; Nagl, Stefan; Kothe, Erika

    2015-01-01

    We are presenting a microfluidic droplet-based system for non-invasive, simultaneous optical monitoring of oxygen during bacterial cultivation in nL-sized droplets using ∼350 nm nanobeads made from polystyrene and doped with the NIR-emitting oxygen probe platinum (II) 5, 10, 15, 20-meso-tetraphenyltetrabenzoporphyrin (PtTPTBP). Data were readout by a two-channel micro flow-through fluorimeter and a two-channel micro flow-through photometer. The time-resolved miniaturized optical multi endpoint detection was applied to simultaneously sense dissolved oxygen, cellular autofluorescence, and cell density in nL-sized segments. Two bacterial strains were studied that are resistant to heavy metal ions, viz. Streptomyces acidiscabies E13 and Psychrobacillus psychrodurans UrPLO1. The study has two main features in that it demonstrates (a) the possibility to monitor the changes in oxygen partial pressure during metabolic activity of different bacterial cultures inside droplets, and (b) the efficiency of droplet-based microfluidic techniques along with multi-parameter optical sensing for highly resolved microtoxicological screenings in aquatic systems. (author)

  4. Biocatalyst Screening with a Twist: Application of Oxygen Sensors Integrated in Microchannels for Screening Whole Cell Biocatalyst Variants

    DEFF Research Database (Denmark)

    Fernandes, Ana C.; Halder, Julia M.; Nestl, Bettina M.

    2018-01-01

    Selective oxidative functionalization of molecules is a highly relevant and often demanding reaction in organic chemistry. The use of biocatalysts allows the stereo- and regioselective introduction of oxygen molecules in organic compounds at milder conditions and avoids the use of complex group-p...

  5. Differential signal pathway activation and 5-HT function: the role of gut enterochromaffin cells as oxygen sensors.

    Science.gov (United States)

    Haugen, Martin; Dammen, Rikard; Svejda, Bernhard; Gustafsson, Bjorn I; Pfragner, Roswitha; Modlin, Irvin; Kidd, Mark

    2012-11-15

    The chemomechanosensory function of the gut enterochromaffin (EC) cell enables it to respond to dietary agents and mechanical stretch. We hypothesized that the EC cell, which also sensed alterations in luminal or mucosal oxygen level, was physiologically sensitive to fluctuations in O(2). Given that low oxygen levels induce 5-HT production and secretion through a hypoxia inducible factor 1α (HIF-1α)-dependent pathway, we also hypothesized that increasing O(2) would reduce 5-HT production and secretion. Isolated normal EC cells as well as the well-characterized EC cell model KRJ-I were used to examine HIF signaling (luciferase-assays), hypoxia transcriptional response element (HRE)-mediated transcription (PCR), signaling pathways (Western blot), and 5-HT release (ELISA) during exposure to different oxygen levels. Normal EC cells and KRJ-I cells express HIF-1α, and transient transfection with Renilla luciferase under HRE control identified a hypoxia-mediated pathway in these cells. PCR confirmed activation of HIF-downstream targets, GLUT1, IGF2, and VEGF under reduced O(2) levels (0.5%). Reducing O(2) also elevated 5-HT secretion (2-3.2-fold) as well as protein levels of HIF-1α (1.7-3-fold). Increasing O(2) to 100% inhibited HRE-mediated signaling, transcription, reduced 5-HT secretion, and significantly lowered HIF-1α levels (∼75% of control). NF-κB signaling was also elevated during hypoxia (1.2-1.6-fold), but no significant changes were noted in PKA/cAMP. We concluded that gut EC cells are oxygen responsive, and alterations in O(2) levels differentially activate HIF-1α and tryptophan hydroxylase 1, as well as NF-κB signaling. This results in alterations in 5-HT production and secretion and identifies that the chemomechanosensory role of EC cells extends to oxygen sensing.

  6. Extracellular histones induce erythrocyte fragility and anemia.

    Science.gov (United States)

    Kordbacheh, Farzaneh; O'Meara, Connor H; Coupland, Lucy A; Lelliott, Patrick M; Parish, Christopher R

    2017-12-28

    Extracellular histones have been shown to play an important pathogenic role in many diseases, primarily through their cytotoxicity toward nucleated cells and their ability to promote platelet activation with resultant thrombosis and thrombocytopenia. In contrast, little is known about the effect of extracellular histones on erythrocyte function. We demonstrate in this study that histones promote erythrocyte aggregation, sedimentation, and using a novel in vitro shear stress model, we show that histones induce erythrocyte fragility and lysis in a concentration-dependent manner. Furthermore, histones impair erythrocyte deformability based on reduced passage of erythrocytes through an artificial spleen. These in vitro results were mirrored in vivo with the injection of histones inducing anemia within minutes of administration, with a concomitant increase in splenic hemoglobin content. Thrombocytopenia and leukopenia were also observed. These findings suggest that histones binding to erythrocytes may contribute to the elevated erythrocyte sedimentation rates observed in inflammatory conditions. Furthermore, histone-induced increases in red blood cell lysis and splenic clearance may be a significant factor in the unexplained anemias seen in critically ill patients. © 2017 by The American Society of Hematology.

  7. Effects of Radiographic Contrast Media on the Micromorphology of the Junctional Complex of Erythrocytes Visualized by Immunocytology

    Science.gov (United States)

    Franke, Ralf-Peter; Krüger, Anne; Scharnweber, Tim; Wenzel, Folker; Jung, Friedrich

    2014-01-01

    Effects of radiographic contrast media (RCM) application were demonstrated in vitro and in vivo where the injection of RCM into the A. axillaris of patients with coronary artery disease was followed by a significant and RCM-dependent decrease of erythrocyte velocity in downstream skin capillaries. Another study in pigs revealed that the deceleration of erythrocytes coincided with a significant reduction of the oxygen partial pressure in the myocardium—supplied by the left coronary artery—after the administration of RCM into this artery. Further reports showed RCM dependent alterations of erythrocytes like echinocyte formation and exocytosis, sequestration of actin or band 3 and the buckling of endothelial cells coinciding with a formation of interendothelial fenestrations leading to areas devoid of endothelial cells. Key to morphological alterations of erythrocytes is the membrane cytoskeleton, which is linked to the band 3 in the erythrocyte membrane via the junctional complex. Fundamental observations regarding the cell biological and biochemical aspects of the structure and function of the cell membrane and the membrane cytoskeleton of erythrocytes have been reported. This review focuses on recent results gained, e.g., by advanced confocal laser scanning microscopy of different double-stained structural elements of the erythrocyte membrane cytoskeleton. PMID:25222553

  8. Investigation of photoplethysmographic signals and blood oxygen saturation values on healthy volunteers during cuff-induced hypoperfusion using a multimode PPG/SpO₂ sensor.

    Science.gov (United States)

    Shafique, M; Kyriacou, P A; Pal, S K

    2012-06-01

    Photoplethysmography (PPG) is a technique widely used to monitor volumetric blood changes induced by cardiac pulsations. Pulse oximetry uses the technique of PPG to estimate arterial oxygen saturation values (SpO₂). In poorly perfused tissues, SpO₂ readings may be compromised due to the poor quality of the PPG signals. A multimode finger PPG probe that operates simultaneously in reflectance, transmittance and a combined mode called "transreflectance" was developed, in an effort to improve the quality of the PPG signals in states of hypoperfusion. Experiments on 20 volunteers were conducted to evaluate the performance of the multimode PPG sensor and compare the results with a commercial transmittance pulse oximeter. A brachial blood pressure cuff was used to induce artificial hypoperfusion. Results showed that the amplitude of the transreflectance AC PPG signals were significantly different (p signals obtained from the other two conventional PPG sensors (reflectance and transmittance). At induced brachial pressures between 90 and 135 mmHg, the reflectance finger pulse oximeter failed 25 times (failure rate 42.2 %) to estimate SpO₂ values, whereas the transmittance pulse oximeter failed 8 times (failure rate 15.5 %). The transreflectance pulse oximeter failed only 3 times (failure rate 6.8 %) and the commercial pulse oximeter failed 17 times (failure rate 29.4 %).

  9. Induction of transient radioresistance in human erythrocytes

    International Nuclear Information System (INIS)

    Krokosz, Anita; Szweda-Lewandowska, Zofia

    2006-01-01

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%), were irradiated with γ-rays with single and split doses under air or N 2 O in order to determine the physicochemical changes caused by the dose inducing an increase in resistance to radiation-induced hemolysis. The obtained results showed that under the applied irradiation conditions, the dose of 0.4 kGy induced changes in erythrocytes, which were responsible for temporary resistance of erythrocytes to hemolysis. We concluded that the observed resistance is caused mainly by the structural changes in proteins

  10. The AMP-activated protein kinase beta 1 subunit modulates erythrocyte integrity.

    Science.gov (United States)

    Cambridge, Emma L; McIntyre, Zoe; Clare, Simon; Arends, Mark J; Goulding, David; Isherwood, Christopher; Caetano, Susana S; Reviriego, Carmen Ballesteros; Swiatkowska, Agnieszka; Kane, Leanne; Harcourt, Katherine; Adams, David J; White, Jacqueline K; Speak, Anneliese O

    2017-01-01

    Failure to maintain a normal in vivo erythrocyte half-life results in the development of hemolytic anemia. Half-life is affected by numerous factors, including energy balance, electrolyte gradients, reactive oxygen species, and membrane plasticity. The heterotrimeric AMP-activated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that acts as a critical regulator of cellular energy balance. Previous roles for the alpha 1 and gamma 1 subunits in the control of erythrocyte survival have been reported. In the work described here, we studied the role of the beta 1 subunit in erythrocytes and observed microcytic anemia with compensatory extramedullary hematopoiesis together with splenomegaly and increased osmotic resistance. Copyright © 2016 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

  11. Grape (Vitis vinifera) extracts protects against radiation-induced oxidative stress in human erythrocyte (RBC)

    International Nuclear Information System (INIS)

    Ghosh, Subhashis

    2016-01-01

    Ionizing radiation (IR) causes oxidative stress through the overwhelming generation of reactive oxygen species (ROS) in the living cells leading further to the oxidative damage to biomolecules. Grapes (Vitis vinifera) contain several bioactive phytochemicals and are the richest source of antioxidant. In this study, we investigated the radioprotective actions of the grape extracts of two different cultivars, including the Thompson seedless (green) and Kishmish chorni (black) in human erythrocytes. Pretreatment with grape extracts attenuates oxidative stress induced by 4 Gy-radiation in human erythrocytes in vitro. These results suggest that grape extract serve as a potential source of natural antioxidants against the IR-induced oxidative stress and also inhibit apoptosis. Furthermore, the protective action of grape depends on the source of extract (seed, skin or pulp) and type of the cultivars. Effects of grape extracts of different cultivars on protein content, Thiobarbituric acid reactive substances (TBARS) level, reduced glutathione (GSH) content and activities of Catalase, Nitrite, GST, GR in human erythrocytes against -radiation exposure at a dose of 4 Gy are investigated. The grape extracts did not appear to alter the viability of human erythrocytes. Exposure of erythrocytes to the -irradiation at a dose of 4 Gy significantly increased the extent of formation of TBARS, while decreased the level of GSH and activities of CAT, GSSG , GST, GR in the erythrocytes as compared to the non-irradiated control counterparts. This was significantly attenuated by the pretreatment with the grape seed extracts (p<0.001) and significantly with the skin extracts (p<0.05) compared to the ionizing radiation exposed group. Moreover, protection offered by the seed extracts was found significantly better than that was offered by the pulp extract of the same cultivar. In conclusion, our results suggested that the grape extracts significantly attenuated IR induced oxidative stress and

  12. Erythrocytes Are Oxygen-Sensing Regulators of the Cerebral Microcirculation

    DEFF Research Database (Denmark)

    Wei, Helen Shinru; Kang, Hongyi; Rasheed, Izad-Yar Daniel

    2016-01-01

    and neuronal activity. Since capillaries are embedded in the O2-consuming neuropil, we have here examined whether activity-dependent dips in O2 tension drive capillary hyperemia. In vivo analyses showed that transient dips in tissue O2 tension elicit capillary hyperemia. Ex vivo experiments revealed that red...

  13. Structural characterization of the heme-based oxygen sensor, AfGcHK, its interactions with the cognate response regulator, and their combined mechanism of action in a bacterial two-component signaling system

    Czech Academy of Sciences Publication Activity Database

    Stráňava, M.; Martínek, V.; Man, Petr; Fojtíková, V.; Kavan, Daniel; Vaněk, O.; Shimizu, T.; Martínková, M.

    2016-01-01

    Roč. 84, č. 10 (2016), s. 1375-1389 ISSN 1097-0134 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : heme-based oxygen sensor * histidine kinase * two-component signal transduction system Subject RIV: CE - Biochemistry

  14. Sensor employing internal reference electrode

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention concerns a novel internal reference electrode as well as a novel sensing electrode for an improved internal reference oxygen sensor and the sensor employing same.......The present invention concerns a novel internal reference electrode as well as a novel sensing electrode for an improved internal reference oxygen sensor and the sensor employing same....

  15. Curcumin Protects -SH Groups and Sulphate Transport after Oxidative Damage in Human Erythrocytes

    Directory of Open Access Journals (Sweden)

    Rossana Morabito

    2015-05-01

    Full Text Available Background/Aims: Erythrocytes, continuously exposed to oxygen pressure and toxic compounds, are sensitive to oxidative stress, namely acting on integral Band 3 protein, with consequences on cell membranes deformability and anion transport efficiency. The aim of the present investigation, conducted on human erythrocytes, is to verify whether curcumin (1 or 10µM, a natural compound with proved antioxidant properties, may counteract Band 3-mediated anion transport alterations due to oxidative stress. Methods: Oxidative conditions were induced by exposure to, alternatively, either 2 mM N-ethylmaleimide (NEM or pH-modified solutions (6.5 and 8.5. Rate constant for SO4= uptake and -SH groups estimation were measured to verify the effect of oxidative stress on anion transport efficiency and erythrocyte membranes. Results: After the exposure of erythrocytes to, alternatively, NEM or pH-modified solutions, a significant decrease in both rate constant for SO4= uptake and -SH groups was observed, which was prevented by curcumin, with a dose-dependent effect. Conclusions: Our results show that: i the decreased efficiency of anion transport may be due to changes in Band 3 protein structure caused by cysteine -SH groups oxidation, especially after exposure to NEM and pH 6.5; ii 10 µM Curcumin is effective in protecting erythrocytes from oxidative stress events at level of cell membrane transport.

  16. Oxygen sensors and energy sensors act synergistically to achieve a graded alteration in gene expression: consequences for assessing the level of neuroprotection in response to stressors.

    Science.gov (United States)

    Renshaw, Gillian M C; Warburton, Joshua; Girjes, Adeeb

    2004-01-01

    Changes in gene expression are associated with switching to an autoprotected phenotype in response to environmental and physiological stress. Ubiquitous molecular chaperones from the heat shock protein (HSP) superfamily confer neuronal protection that can be blocked by antibodies. Recent research has focused on the interactions between the molecular sensors that affect the increased expression of neuroprotective HSPs above constitutive levels. An examination of the conditions under which the expression of heat shock protein 70 (Hsp70) was up regulated in a hypoxia and anoxia tolerant tropical species, the epaulette shark (Hemiscyllium ocellatum), revealed that up-regulation was dependent on exceeding a stimulus threshold for an oxidative stressor. While hypoxic-preconditioning confers neuroprotective changes, there was no increase in the level of Hsp70 indicating that its increased expression was not associated with achieving a neuroprotected state in response to hypoxia in the epaulette shark. Conversely, there was a significant increase in Hsp70 in response to anoxic-preconditioning, highlighting the presence of a stimulus threshold barrier and raising the possibility that, in this species, Hsp70 contributes to the neuroprotective response to extreme crises, such as oxidative stress. Interestingly, there was a synergistic effect of coincident stressors on Hsp70 expression, which was revealed when metabolic stress was superimposed upon oxidative stress. Brain energy charge was significantly lower when adenosine receptor blockade, provided by treatment with aminophylline, was present prior to the final anoxic episode, under these circumstances, the level of Hsp70 induced was significantly higher than in the pair-matched saline treated controls. An understanding of the molecular and metabolic basis for neuroprotective switches, which result in an up-regulation of neuroprotective Hsp70 expression in the brain, is needed so that intervention strategies can be devised

  17. Kinetic Investigations of the Role of Factor Inhibiting Hypoxia-inducible Factor (FIH) as an Oxygen Sensor.

    Science.gov (United States)

    Tarhonskaya, Hanna; Hardy, Adam P; Howe, Emily A; Loik, Nikita D; Kramer, Holger B; McCullagh, James S O; Schofield, Christopher J; Flashman, Emily

    2015-08-07

    The hypoxia-inducible factor (HIF) hydroxylases regulate hypoxia sensing in animals. In humans, they comprise three prolyl hydroxylases (PHD1-3 or EGLN1-3) and factor inhibiting HIF (FIH). FIH is an asparaginyl hydroxylase catalyzing post-translational modification of HIF-α, resulting in reduction of HIF-mediated transcription. Like the PHDs, FIH is proposed to have a hypoxia-sensing role in cells, enabling responses to changes in cellular O2 availability. PHD2, the most important human PHD isoform, is proposed to be biochemically/kinetically suited as a hypoxia sensor due to its relatively high sensitivity to changes in O2 concentration and slow reaction with O2. To ascertain whether these parameters are conserved among the HIF hydroxylases, we compared the reactions of FIH and PHD2 with O2. Consistent with previous reports, we found lower Km(app)(O2) values for FIH than for PHD2 with all HIF-derived substrates. Under pre-steady-state conditions, the O2-initiated FIH reaction is significantly faster than that of PHD2. We then investigated the kinetics with respect to O2 of the FIH reaction with ankyrin repeat domain (ARD) substrates. FIH has lower Km(app)(O2) values for the tested ARDs than HIF-α substrates, and pre-steady-state O2-initiated reactions were faster with ARDs than with HIF-α substrates. The results correlate with cellular studies showing that FIH is active at lower O2 concentrations than the PHDs and suggest that competition between HIF-α and ARDs for FIH is likely to be biologically relevant, particularly in hypoxic conditions. The overall results are consistent with the proposal that the kinetic properties of individual oxygenases reflect their biological capacity to act as hypoxia sensors. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Adenosine deaminase activity of erythrocytes in hyperuricemia

    International Nuclear Information System (INIS)

    Krueger, W.; Richter, V.; Beenken, O.; Weinhold, D.; Hirschberg, K.; Rotzsch, W.; Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung)

    1982-01-01

    Erythrocytic adenosine deaminase (ADA) activity was determined in 55 patients with primary hyperuricemia and in 37 healthy control persons. Unlike the controls, the ADA activity in the patient group showed a two-peak response. Hyperuricemia patients with high ADA activity also exhibited increased uric acid excretion and elevated 15 N incorporation into uric acid. High activity values of erythrocytic ADA can be interpreted as an uric acid overproduction, giving hints for a therapeutic plan. (author)

  19. Altitude Acclimatization and Blood Volume: Effects of Exogenous Erythrocyte Volume Expansion

    National Research Council Canada - National Science Library

    Sawka, M

    1996-01-01

    ...: (a) altitude acclimatization effects on erythrocyte volume and plasma volume; (b) if exogenous erythrocyte volume expansion alters subsequent erythrocyte volume and plasma volume adaptations; (c...

  20. Coordination and redox state-dependent structural changes of the heme-based oxygen sensor AfGcHK associated with intraprotein signal transduction.

    Science.gov (United States)

    Stranava, Martin; Man, Petr; Skálová, Tereza; Kolenko, Petr; Blaha, Jan; Fojtikova, Veronika; Martínek, Václav; Dohnálek, Jan; Lengalova, Alzbeta; Rosůlek, Michal; Shimizu, Toru; Martínková, Markéta

    2017-12-22

    The heme-based oxygen sensor histidine kinase Af GcHK is part of a two-component signal transduction system in bacteria. O 2 binding to the Fe(II) heme complex of its N-terminal globin domain strongly stimulates autophosphorylation at His 183 in its C-terminal kinase domain. The 6-coordinate heme Fe(III)-OH - and -CN - complexes of Af GcHK are also active, but the 5-coordinate heme Fe(II) complex and the heme-free apo-form are inactive. Here, we determined the crystal structures of the isolated dimeric globin domains of the active Fe(III)-CN - and inactive 5-coordinate Fe(II) forms, revealing striking structural differences on the heme-proximal side of the globin domain. Using hydrogen/deuterium exchange coupled with mass spectrometry to characterize the conformations of the active and inactive forms of full-length Af GcHK in solution, we investigated the intramolecular signal transduction mechanisms. Major differences between the active and inactive forms were observed on the heme-proximal side (helix H5), at the dimerization interface (helices H6 and H7 and loop L7) of the globin domain and in the ATP-binding site (helices H9 and H11) of the kinase domain. Moreover, separation of the sensor and kinase domains, which deactivates catalysis, increased the solvent exposure of the globin domain-dimerization interface (helix H6) as well as the flexibility and solvent exposure of helix H11. Together, these results suggest that structural changes at the heme-proximal side, the globin domain-dimerization interface, and the ATP-binding site are important in the signal transduction mechanism of Af GcHK. We conclude that Af GcHK functions as an ensemble of molecules sampling at least two conformational states. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Insights into signal transduction by a hybrid FixL: Denaturation study of on and off states of a multi-domain oxygen sensor.

    Science.gov (United States)

    Guimarães, Wellinson G; Gondim, Ana C S; Costa, Pedro Mikael da Silva; Gilles-Gonzalez, Marie-Alda; Lopes, Luiz G F; Carepo, Marta S P; Sousa, Eduardo H S

    2017-07-01

    FixL from Rhizobium etli (ReFixL) is a hybrid oxygen sensor protein. Signal transduction in ReFixL is effected by a switch off of the kinase activity on binding of an oxygen molecule to ferrous heme iron in another domain. Cyanide can also inhibit the kinase activity upon binding to the heme iron in the ferric state. The unfolding by urea of the purified full-length ReFixL in both active pentacoordinate form, met-FixL(Fe III ) and inactive cyanomet-FixL (Fe III -CN - ) form was monitored by UV-visible absorption spectroscopy, circular dichroism (CD) and fluorescence spectroscopy. The CD and UV-visible absorption spectroscopy revealed two states during unfolding, whereas fluorescence spectroscopy identified a three-state unfolding mechanism. The unfolding mechanism was not altered for the active compared to the inactive state; however, differences in the ΔG H2O were observed. According to the CD results, compared to cyanomet-FixL, met-FixL was more stable towards chemical denaturation by urea (7.2 vs 4.8kJmol -1 ). By contrast, electronic spectroscopy monitoring of the Soret band showed cyanomet-FixL to be more stable than met-FixL (18.5 versus 36.2kJmol -1 ). For the three-state mechanism exhibited by fluorescence, the ΔG H2O for both denaturation steps were higher for the active-state met-FixL than for cyanomet-FixL. The overall stability of met-FixL is higher in comparison to cyanomet-FixL suggesting a more compact protein in the active form. Nonetheless, hydrogen bonding by bound cyanide in the inactive state promotes the stability of the heme domain. This work supports a model of signal transduction by FixL that is likely shared by other heme-based sensors. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. An applicable approach for extracting human heart rate and oxygen saturation during physical movements using a multi-wavelength illumination optoelectronic sensor system

    Science.gov (United States)

    Alharbi, Samah; Hu, Sijung; Mulvaney, David; Blanos, Panagiotis

    2018-02-01

    The ability to gather physiological parameters such as heart rate (HR) and oxygen saturation (SpO2%) during physical movement allows to continuously monitor personal health status without disrupt their normal daily activities. Photoplethysmography (PPG) based pulse oximetry and similar principle devices are unable to extract the HR and SpO2% reliably during physical movement due to interference in the signals that arise from motion artefacts (MAs). In this research, a flexible reflectance multi-wavelength optoelectronic patch sensor (OEPS) has been developed to overcome the susceptibility of conventional pulse oximetry readings to MAs. The OEPS incorporates light embittered diodes as illumination sources with four different wavelengths, e.g. green, orange, red, and infrared unlike the conventional pulse oximetry devices that normally measure the skin absorption of only two wavelengths (red and infrared). The additional green and orange wavelengths were found to be distinguish to the absorption of deoxyhemoglobin (RHb) and oxyhemoglobin (HbO2). The reliability of extracting physiological parameters from the green and orange wavelengths is due to absorbed near to the surface of the skin, thereby shortening the optical path and so effectively reducing the influence of physical movements. To compensate of MAs, a three-axis accelerometer was used as a reference with help of adaptive filter to reduce MAs. The experiments were performed using 15 healthy subjects aged 20 to 30. The primary results show that there are no significant difference of heart rate and oxygen saturation measurements between commercial devices and OEPS Green (r=0.992), Orange(r=0.984), Red(r=0.952) and IR(r=0.97) and SpO2% (r = 0.982, p = 0.894).

  3. Iron-sulfur clusters as biological sensors: the chemistry of reactions with molecular oxygen and nitric oxide.

    Science.gov (United States)

    Crack, Jason C; Green, Jeffrey; Thomson, Andrew J; Le Brun, Nick E

    2014-10-21

    Iron-sulfur cluster proteins exhibit a range of physicochemical properties that underpin their functional diversity in biology, which includes roles in electron transfer, catalysis, and gene regulation. Transcriptional regulators that utilize iron-sulfur clusters are a growing group that exploit the redox and coordination properties of the clusters to act as sensors of environmental conditions including O2, oxidative and nitrosative stress, and metabolic nutritional status. To understand the mechanism by which a cluster detects such analytes and then generates modulation of DNA-binding affinity, we have undertaken a combined strategy of in vivo and in vitro studies of a range of regulators. In vitro studies of iron-sulfur cluster proteins are particularly challenging because of the inherent reactivity and fragility of the cluster, often necessitating strict anaerobic conditions for all manipulations. Nevertheless, and as discussed in this Account, significant progress has been made over the past decade in studies of O2-sensing by the fumarate and nitrate reduction (FNR) regulator and, more recently, nitric oxide (NO)-sensing by WhiB-like (Wbl) and FNR proteins. Escherichia coli FNR binds a [4Fe-4S] cluster under anaerobic conditions leading to a DNA-binding dimeric form. Exposure to O2 converts the cluster to a [2Fe-2S] form, leading to protein monomerization and hence loss of DNA binding ability. Spectroscopic and kinetic studies have shown that the conversion proceeds via at least two steps and involves a [3Fe-4S](1+) intermediate. The second step involves the release of two bridging sulfide ions from the cluster that, unusually, are not released into solution but rather undergo oxidation to sulfane (S(0)) subsequently forming cysteine persulfides that then coordinate the [2Fe-2S] cluster. Studies of other [4Fe-4S] cluster proteins that undergo oxidative cluster conversion indicate that persulfide formation and coordination may be more common than previously

  4. [The physiologic significance of 2,3-diphosphoglycerate and changes in its erythrocyte levels in an experiment].

    Science.gov (United States)

    Béder, I; Orgonásová, M; Brozman, B; Horecký, J; Mataseje, A

    1990-05-01

    The regulatory effect of 2,3-DPG on oxygen transport and binding to hemoglobin was analyzed. Under conditions of substitution hemodilution by isooncotic 3.4% Rheodextran (Spofa), changes in the content of 2,3-DPG in arterial and venous blood were enzymatically determined over several days. Reference values of 2,3-DPG were obtained in the studied series of dogs (2.05 +/- 0.74 x 10(-6) mol.ml-1 in whole blood 4.69 +/- 1.52 x 10(-6) mol.g-1 of erythrocyte volume, and 13.39 +/- 2.82 x 10(-6) mol.ml-1 of hemoglobin). In anesthetized animals the content of 2,3-DPG in arterial blood was significantly higher (6.28 +/- 0.84 x 10(-6) mol.ml-1 of erythrocyte volume) than in venous blood (6.01 +/- 0.80 x 10(-6) mol.ml-1 of erythrocyte volume). At substitution hemodilution the 2,3-DPG content in erythrocytes of venous blood decreased from 5.46 +/- 0.67 to 4.97 +/- 1.31 x 10(-6) mol.ml-1 of erythrocyte volume. The subsequent increase to 6.04 +/- 0.71 x 10(-6) mol.ml-1 of erythrocyte volume was achieved by nonlinear increase over the following days, at persisting low hemoglobin content in blood.

  5. Allosensibilisation to erythrocyte antigens (literature review

    Directory of Open Access Journals (Sweden)

    N. V. Mineeva

    2015-01-01

    Full Text Available In this article literature review of the causes of allosensibilisation to erythrocyte antigens are presented. It is shown that the ability to produce antierythrocyte antibodies is affected by many factors, principal of whom it is difficult to identify. For the allosensibilisation development requires genetically determined differences in erythrocyte antigens phenotypes of donor and recipient, mother and fetus, which can lead to immune response and antibodies production. The biochemical nature of erythrocyte antigens, antigen dose (the amount of transfused doses, the number of antigens determinants on donor and fetus erythrocytes, the number of pregnancies are important. Individual patient characteristics: age, gender, diseases, the use of immunosuppressive therapy and the presence of inflammatory processes, are also relevant. Note that antibody to one erythrocyte antigens have clinical value, and to the other – have no. The actual data about frequency of clinically significant antibodies contribute to the development of post-transfusion hemolytic complications prophylaxis as well as the improvement of laboratory diagnosis of hemolytic disease of the newborn in the presence of maternal antierythrocyte antibodies.

  6. Inhibition of Suicidal Erythrocyte Death by Indirubin-3’-Monoxime

    Directory of Open Access Journals (Sweden)

    Chunqiu Liu

    2018-02-01

    Full Text Available Background/Aims: Qing Dai is a prized traditional Chinese medicine whose major component, indirubin, and its derivative, indirubin-3’-monoxime (IDM, have inhibitory effects on the growth of many human tumor cells and pronounced anti-leukemic activities. However, the effects of IDM on mature human erythrocytes are unclear. This study aimed to evaluate the potential impact of IDM on erythrocytes and the mechanisms underlying that impact. Methods: Utilizing flow cytometry and confocal laser scanning microscopy, phosphatidylserine exposure at the cell surface was estimated by annexin V-fluorescein isothiocyanate (FITC. The relative cell size, expressed in arbitrary units, was evaluated by forward scatter in a flow cytometer. Fluo-3 fluorescence was used to bewrite changes in cytosolic Ca2+ activity, reactive oxygen species (ROS formation was assessed by 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA fluorescence, and ceramide abundance was evaluated by FITC-conjugated specific antibodies. Results: The 24-h exposure of human erythrocytes to IDM (12 µM significantly decreased the percentage of annexin V-binding erythrocytes and the intracellular calcium concentration ([Ca2+]i. IDM (3-12 µM did not significantly modify the ceramide level or DCFH-DA fluorescence. Energy depletion (removal of glucose for 24 hours significantly increased annexin V binding and Fluo-3 fluorescence and diminished forward scatter, and these effects were significantly mitigated by IDM (12 µM. Moreover, the Ca2+ ionophore ionomycin (1 µM, 60 min and oxidative stress (30 min exposure to 0.05 mM tert-butyl hydroperoxide, t-BHP similarly triggered eryptosis, which was also significantly suppressed by IDM. Conclusions: IDM is a novel inhibitor of suicidal erythrocyte death following ionomycin treatment, t-BHP treatment and energy depletion. Thus, IDM may counteract anemia and impairment of microcirculation, at least in part, by inhibition of Ca2+ entry into erythrocytes.

  7. Assessment and Use of Optical Oxygen Sensors as Tools to Assist in Optimal Product Component Selection for the Development of Packs of Ready-to-Eat Mixed Salads and for the Non-Destructive Monitoring of in-Pack Oxygen Levels Using Chilled Storage.

    Science.gov (United States)

    Hempel, Andreas W; O'Sullivan, Maurice G; Papkovsky, Dmitri B; Kerry, Joseph P

    2013-05-22

    Optical oxygen sensors were used to ascertain the level of oxygen consumed by individual salad leaves for optimised packaging of ready-to-eat (RTE) Italian salad mixes during refrigerated storage. Seven commonly found leaves in Italian salad mixes were individually assessed for oxygen utilisation in packs. Each leaf showed varying levels of respiration throughout storage. Using the information obtained, an experimental salad mix was formulated (termed Mix 3) which consisted of the four slowest respiring salad leaves-Escarole, Frisee, Red Batavia, Lollo Rosso. Mix 3 was then compared against two commercially available Italian salads; Mix 1 (Escarole, Frisee, Radicchio, Lollo Rosso) and Mix 2 (Cos, Frisee, Radicchio, Lollo Rosso). Optical sensors were used to non-destructively monitor oxygen usage in all mixes throughout storage. In addition to oxygen consumption, all three salad mixes were quality assessed in terms of microbial load and sensorial acceptability. In conclusion, Mix 3 was found to consume the least amount of oxygen over time, had the lowest microbial load and was most sensorially preferred ( p products.

  8. Physical and Chemical Processes and the Morphofunctional Characteristics of Human Erythrocytes in Hyperglycaemia

    Directory of Open Access Journals (Sweden)

    Victor V. Revin

    2017-08-01

    Full Text Available Background: This study examines the effect of graduated hyperglycaemia on the state and oxygen-binding ability of hemoglobin, the correlation of phospholipid fractions and their metabolites in the membrane, the activity of proteolytic enzymes and the morphofunctional state of erythrocytes.Methods: Conformational changes in the molecule of hemoglobin were determined by Raman spectroscopy. The structure of the erythrocytes was analyzed using laser interference microscopy (LIM. To determine the activity of NADN-methemoglobinreductase, we used the P.G. Board method. The degree of glycosylation of the erythrocyte membranes was determined using a method previously described by Felkoren et al. Lipid extraction was performed using the Bligh and Dyer method. Detection of the phospholipids was performed using V. E. Vaskovsky method.Results: Conditions of hyperglycaemia are characterized by a low affinity of hemoglobin to oxygen, which is manifested as a parallel decrease in the content of hemoglobin oxyform and the growth of deoxyform, methemoglobin and membrane-bound hemoglobin. The degree of glycosylation of membrane proteins and hemoglobin is high. For example, in the case of hyperglycaemia, erythrocytic membranes reduce the content of all phospholipid fractions with a simultaneous increase in lysoforms, free fatty acids and the diacylglycerol (DAG. Step wise hyperglycaemia in incubation medium and human erythrocytes results in an increased content of peptide components and general trypsin-like activity in the cytosol, with a simultaneous decreased activity of μ-calpain and caspase 3.Conclusions: Metabolic disorders and damage of cell membranes during hyperglycaemia cause an increase in the population of echinocytes and spherocytes. The resulting disorders are accompanied with a high probability of intravascular haemolysis.

  9. Erythrocyte Membrane Failure by Electromechanical Stress

    Directory of Open Access Journals (Sweden)

    E Du

    2018-01-01

    Full Text Available We envision that electrodeformation of biological cells through dielectrophoresis as a new technique to elucidate the mechanistic details underlying membrane failure by electrical and mechanical stresses. Here we demonstrate the full control of cellular uniaxial deformation and tensile recovery in biological cells via amplitude-modified electric field at radio frequency by an interdigitated electrode array in microfluidics. Transient creep and cyclic experiments were performed on individually tracked human erythrocytes. Observations of the viscoelastic-to-viscoplastic deformation behavior and the localized plastic deformations in erythrocyte membranes suggest that electromechanical stress results in irreversible membrane failure. Examples of membrane failure can be separated into different groups according to the loading scenarios: mechanical stiffening, physical damage, morphological transformation from discocyte to echinocyte, and whole cell lysis. These results show that this technique can be potentially utilized to explore membrane failure in erythrocytes affected by other pathophysiological processes.

  10. Influence of styryl dyes on blood erythrocytes

    Science.gov (United States)

    Nizomov, Negmat; Barakaeva, Mubaro; Kurtaliev, Eldar N.; Rahimov, Sherzod I.; Khakimova, Dilorom P.; Khodjayev, Gayrat; Yashchuk, Valeriy N.

    2008-08-01

    It was studied the influence of F, Sbt, Sil, Sbo monomer and homodimer Dst-5, Dst-10, Dbt-5, Dbt-10, Dil-10, Dbo-10 styryl dyes on blood erythrocytes of white rats. It was shown that the homodimer styryl dyes Dst-5, Dbt-5 and Dbo-10 decrease the erythrocytes quantity by 1.5-2 times more as compared with monomer dyes Sbt and Sbo. The main cause of dyes different action is the different oxidation degree of intracellular hemoglobin evoked by these dyes. It was established that the observed effects was connected with different penetration of these dyes through membrane of erythrocytes and with interaction of these dyes with albumin localized in membranes of cells.

  11. Cryo scanning electron microscopy of Plasmodium falciparum-infected erythrocytes

    DEFF Research Database (Denmark)

    Hempel, Casper

    2017-01-01

    Plasmodium falciparum invades erythrocytes as an essential part of their life cycle. While living inside erythrocytes, the parasite remodels the cell's intracellular organization as well as its outer surface. Late trophozoite-stage parasites and schizonts introduce numerous small protrusions...

  12. Role of erythrocyte tropomodulin in the biomechanics and topology of the erythrocyte membrane skeletal network

    OpenAIRE

    Green, Terrell Ann

    2010-01-01

    The erythrocyte membrane skeleton is a multi-protein complex providing mechanical properties and stability to erythrocytes. Defects in the skeleton can manifest in dysfunction and disease such as hemolytic anemia. Erythrocyte tropomodulin (E-Tmod) is a slow-growing end actin-capping protein and has been proposed that together with tropomyosin 5 or 5b they form a "molecular ruler" which dictates protofilament length of 37 nm in the network. In this study, the role for E-Tmod in the network org...

  13. Paired Chicken and Mammalian Erythrocyte Indicator Systems for ...

    African Journals Online (AJOL)

    Three levels of erythrocytes suspensions, 1.5%, 1% and 0.5% respectively from goat and guinea pig, were compared to conventional 0.5% chicken erythrocytes, in an attempt to investigate the suitability for the two sources of mammalian erythrocytes as indicators for Newcastle disease virus haemagglutination (HA) tests.

  14. Effect of pH on molecular constitution and distribution of hemoglobin in living erythrocyte.

    Science.gov (United States)

    Wu, Yue; Huang, Yao-Xiong; Kang, Li-Li; Wu, Zheng-Jie; Luo, Man

    2010-04-01

    The molecular constitution of in situ hemoglobin (Hb) and their distribution in living erythrocyte were investigated versus pH using the technique of confocal Raman microscopy. Both Raman point spectra and line mapping measurements were performed on living erythrocytes in suspensions with pH values from 4.82 to 9.70. It was found that the Hb inside a living erythrocyte would dissociate into monomer/dimer when the cells are in low and high pH environments. In contrast to the homogeneous distribution of the Hbs in the cells in neutral suspension, there are more Hbs distributing around the cell membrane or binding to the membrane as pH increases. While in low pH, as the cell become spherical, most of the Hbs distribute to the central part of the cell. In summary, our investigation suggests that the variation of the external pH not only brings changes in the morphology and membrane structure of an erythrocyte, but also affects the constitution and distribution of its intracellular Hbs, thereby the flexibility of the cell membrane and the oxygenation ability of the Hb.

  15. Purification and Partial Characterization of Catalase from Chicken Erythrocytes and the Effect of Various Inhibitors on Enzyme Activity

    OpenAIRE

    AYDEMİR, Tülin; KURU, Kevser

    2003-01-01

    Catalase plays a major role in the protection of tissues from the toxic effects of H2O2 and partially reduced oxygen species. A nearly 136-fold enzyme purification was obtained from chicken erythrocyte by acetone precipitation, ethanol-chloroform treatment, CM-cellulose and Sephadex G-200 chromatography. The specific activity of purified enzyme was 42,556 U/mg. The molecular weight of the native chicken erythrocyte catalase was estimated at 240 kDa by gel filtration. SDS-gel electr...

  16. Sickle erythrocytes enhance phenylephrine and histamine ...

    African Journals Online (AJOL)

    Sickle erythrocytes enhance phenylephrine and histamine contractions of isolated rabbit carotid arteries. ... enhancement of histamine contractions, compared with phenylephrine (in AS and SS), suggests a possible role for histamine in the increased vascular tone and vaso-occlusive crisis in sickle cell disease.

  17. Baseline Haematology and Erythrocyte Morphological Changes of ...

    African Journals Online (AJOL)

    Summary: This study evaluates the haematological parameters and the observed erythrocytes morphological changes in dogs raised in Ibadan, Oyo State in the south western part of Nigeria. Blood samples were collected from sixty-four apparently healthy dogs. The haematological parameters of the blood samples ...

  18. Erythrocyte aging in sickle cell disease.

    NARCIS (Netherlands)

    Bosman, G.J.C.G.M.

    2004-01-01

    Physiological removal of old erythrocytes from the circulation by macrophages is initiated by binding of autologous IgG to senescent cell antigen (SCA). SCA is generated from the anion exchanger band 3. This process is accompanied by a number of alterations in the function and structure of band 3.

  19. Erythrocyte seditnentation rate in elderly blacks

    African Journals Online (AJOL)

    Abstract This study inv~tigated the erythrocyte sedimen- tation rate (ESR) in an elderly population with the objective of establishing reference ranges and the diagnostic value of the ESR. Elderly blacks were randomly selected frOIn conununities in the. Orange Free State. ESR determinations were done according to the ...

  20. Sickle erythrocytes enhance phenylephrine and histamine

    African Journals Online (AJOL)

    Dr Olaleye

    the influence of sickle erythrocyte on contractile responses induced by phenylephrine and histamine. ... obtained from subjects of different haemoglobin (Hb) genotypes (AA, AS and SS), under ... the sixth position of the β-chain of the hemoglobin S. Address for ... blood pressure values in sickle cell anaemia subjects as.

  1. Comparative Erythrocytes Osmotic Fragility Test and some ...

    African Journals Online (AJOL)

    Erythrocytes osmotic fragility and haematological parameters of subjects with HbAS (sickle cell trait) and HbSS (sickle cell anaemia) were determined and compared with subjects with HbAA (normal adult haemoglobin), which acted as control. They were divided into three groups of 40 subjects for HbAA, 35 subjects for ...

  2. Conjugated Bilirubin Triggers Anemia by Inducing Erythrocyte Death

    Science.gov (United States)

    Lang, Elisabeth; Gatidis, Sergios; Freise, Noemi F; Bock, Hans; Kubitz, Ralf; Lauermann, Christian; Orth, Hans Martin; Klindt, Caroline; Schuier, Maximilian; Keitel, Verena; Reich, Maria; Liu, Guilai; Schmidt, Sebastian; Xu, Haifeng C; Qadri, Syed M; Herebian, Diran; Pandyra, Aleksandra A; Mayatepek, Ertan; Gulbins, Erich; Lang, Florian; Häussinger, Dieter; Lang, Karl S; Föller, Michael; Lang, Philipp A

    2015-01-01

    Hepatic failure is commonly associated with anemia, which may result from gastrointestinal bleeding, vitamin deficiency, or liver-damaging diseases, such as infection and alcohol intoxication. At least in theory, anemia during hepatic failure may result from accelerated clearance of circulating erythrocytes. Here we show that bile duct ligation (BDL) in mice leads to severe anemia despite increased reticulocyte numbers. Bilirubin stimulated suicidal death of human erythrocytes. Mechanistically, bilirubin triggered rapid Ca2+ influx, sphingomyelinase activation, formation of ceramide, and subsequent translocation of phosphatidylserine to the erythrocyte surface. Consistent with our in vitro and in vivo findings, incubation of erythrocytes in serum from patients with liver disease induced suicidal death of erythrocytes in relation to their plasma bilirubin concentration. Consistently, patients with hyperbilirubinemia had significantly lower erythrocyte and significantly higher reticulocyte counts compared to patients with low bilirubin levels. Conclusion: Bilirubin triggers suicidal erythrocyte death, thus contributing to anemia during liver disease. (Hepatology 2015;61:275–284) PMID:25065608

  3. Radiation damage to human erythrocytes. Relative contribution of hydroxyl and chloride radicals in N2O-saturated buffers

    International Nuclear Information System (INIS)

    Krokosz, Anita; Komorowska, Magdalena A.; Szweda-Lewandowska, Zofia

    2008-01-01

    The erythrocyte suspensions in Na-phosphate buffered isotonic NaCl solution (PBS) or Na-phosphate isotonic buffer (PB) (hematocrit 1%) were irradiated with the dose of 400 Gy under N 2 O. Erythrocytes were incubated in the medium in which the cells were irradiated or in fresh PBS. The level of damage to cells was estimated on the basis of the course of post-radiation hemolysis and hemoglobin (Hb) oxidation. The medium in which the cells were irradiated and incubated influenced the course of the post-radiation hemolysis and Hb oxidation as well as some other parameters. We discussed the contribution of hydroxyl and chloride radicals in the initiation of erythrocyte damage and oxygen modification of these processes

  4. Introduction of water into the heme distal side by Leu65 mutations of an oxygen sensor, YddV, generates verdoheme and carbon monoxide, exerting the heme oxygenase reaction.

    Science.gov (United States)

    Stranava, Martin; Martínková, Markéta; Stiborová, Marie; Man, Petr; Kitanishi, Kenichi; Muchová, Lucie; Vítek, Libor; Martínek, Václav; Shimizu, Toru

    2014-11-01

    The globin-coupled oxygen sensor, YddV, is a heme-based oxygen sensor diguanylate cyclase. Oxygen binding to the heme Fe(II) complex in the N-terminal sensor domain of this enzyme substantially enhances its diguanylate cyclase activity which is conducted in the C-terminal functional domain. Leu65 is located on the heme distal side and is important for keeping the stability of the heme Fe(II)-O2 complex by preventing the entry of the water molecule to the heme complex. In the present study, it was found that (i) Escherichia coli-overexpressed and purified L65N mutant of the isolated heme-bound domain of YddV (YddV-heme) contained the verdoheme iron complex and other modified heme complexes as determined by optical absorption spectroscopy and mass spectrometry; (ii) CO was generated in the reconstituted system composed of heme-bound L65N and NADPH:cytochrome P450 reductase as confirmed by gas chromatography; (iii) CO generation of heme-bound L65N in the reconstituted system was inhibited by superoxide dismutase and catalase. In a concordance with the result, the reactive oxygen species increased the CO generation; (iv) the E. coli cells overexpressing the L65N protein of YddV-heme also formed significant amounts of CO compared to the cells overexpressing the wild type protein; (v) generation of verdoheme and CO was also observed for other mutants at Leu65 as well, but to a lesser extent. Since Leu65 mutations are assumed to introduce the water molecule into the heme distal side of YddV-heme, it is suggested that the water molecule would significantly contribute to facilitating heme oxygenase reactions for the Leu65 mutants. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Effects of Iron Overload on the Activity of Na,K-ATPase and Lipid Profile of the Human Erythrocyte Membrane.

    Directory of Open Access Journals (Sweden)

    Leilismara Sousa

    Full Text Available Iron is an essential chemical element for human life. However, in some pathological conditions, such as hereditary hemochromatosis type 1 (HH1, iron overload induces the production of reactive oxygen species that may lead to lipid peroxidation and a change in the plasma-membrane lipid profile. In this study, we investigated whether iron overload interferes with the Na,K-ATPase activity of the plasma membrane by studying erythrocytes that were obtained from the whole blood of patients suffering from iron overload. Additionally, we treated erythrocytes of normal subjects with 0.8 mM H2O2 and 1 μM FeCl3 for 24 h. We then analyzed the lipid profile, lipid peroxidation and Na,K-ATPase activity of plasma membranes derived from these cells. Iron overload was more frequent in men (87.5% than in women and was associated with an increase (446% in lipid peroxidation, as indicated by the amount of the thiobarbituric acid reactive substances (TBARS and an increase (327% in the Na,K-ATPase activity in the plasma membrane of erythrocytes. Erythrocytes treated with 1 μM FeCl3 for 24 h showed an increase (132% in the Na,K-ATPase activity but no change in the TBARS levels. Iron treatment also decreased the cholesterol and phospholipid content of the erythrocyte membranes and similar decreases were observed in iron overload patients. In contrast, erythrocytes treated with 0.8 mM H2O2 for 24 h showed no change in the measured parameters. These results indicate that erythrocytes from patients with iron overload exhibit higher Na,K-ATPase activity compared with normal subjects and that this effect is specifically associated with altered iron levels.

  6. Erythrocytes labelling for to value bleeding of digestive tract in pediatrics

    International Nuclear Information System (INIS)

    Mora, R.

    2002-01-01

    The erythrocytes labelling has been facilitated by several factors: a) They are the cellular elements more abundant in the blood (5 x 10 9 / ml blood). b) They are easy to be isolated and manipulated In vitro and they are not very sensitive to the physical or chemical damages. c) They do not depend on energy or nutritious requirements as another cellular elements In vitro. d) With respect to another cells they show an easier labelling with radionuclides due to the availability of a variety of transporter mechanisms and of internal hemoglobin which is rich in active metal with multiple union sites. The erythrocytes are biconcave disks without nucleus composed by a 65% water, 32% hemoglobin and a 3% by lipids and proteins which form the stroma.The hemoglobin is the most important component of erythrocytes, it contains 4 heme groups and one globin molecule (with molecular weight of 68000) and fix iron covalently with 4 atoms of nitrogenated porfyrin. The oxygen is reversibly joined to iron. The hemoglobin does not experiment re-synthesis or degradation during its lifetime in the erythrocyte. It has been stipulated that the diagnostic applications in nuclear medicine are: a) That the radionuclide should have a high intensity of emission with an adequate energy for the image, with minimum particulate radiation and a half life time average similar to the length of the study that is carried out. b) That the radionuclide is joined firmly to the In vivo cells without altering physical and biochemical properties of the cells and their function In vitro. c) That the radionuclide once incorporated to the interior of cell must not be liberated during the study neither reused after of destruction. A quick procedure is now found available for labelling erythrocytes with 99m Tc offering a high performance and quality labelling. This is narrowly related to the 99m Tc chemistry understanding. (Author)

  7. Breakdown of Phosphatidylserine Asymmetry Following Treatment of Erythrocytes with Lumefantrine

    Directory of Open Access Journals (Sweden)

    Kousi Alzoubi

    2014-02-01

    Full Text Available Background: Lumefantrine, a commonly used antimalarial drug, inhibits hemozoin formation in parasites. Several other antimalarial substances counteract parasitemia by triggering suicidal death or eryptosis of infected erythrocytes. Eryptosis is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine-exposure at the erythrocyte surface. Signaling involved in eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i, formation of ceramide, oxidative stress and/or activation of p38 kinase, protein kinase C (PKC, or caspases. The present study explored, whether lumefantrine stimulates eryptosis. Methods: Cell volume has been estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species from 2',7'-dichlorodihydrofluorescein-diacetate fluorescence, content of reduced glutathione (GSH from mercury orange fluorescence, and ceramide abundance from binding of fluorescent antibodies in flow cytometry. Results: A 48 h exposure to lumefantrine (3 µg/mL was followed by a significant increase of annexin-V-binding without significantly altering forward scatter, [Ca2+]i, ROS formation, reduced GSH, or ceramide abundance. The annexin-V-binding following lumefantrine treatment was not significantly modified by p38 kinase inhibitors SB203580 (2 μM and p38 Inh III (1 μM, PKC inhibitor staurosporine (1 µM or pancaspase inhibitor zVAD (1 or 10 µM. Conclusions: Lumefantrine triggers cell membrane scrambling, an effect independent from entry of extracellular Ca2+, ceramide formation, ROS formation, glutathione content, p38 kinase, PKC or caspases.

  8. A gasometric method to determine erythrocyte catalase activity

    Directory of Open Access Journals (Sweden)

    A.J.S. Siqueira

    1999-09-01

    Full Text Available We describe a new gasometric method to determine erythrocyte catalase activity by the measurement of the volume of oxygen produced as a result of hydrogen peroxide decomposition in a system where enzyme and substrate are separated in a special reaction test tube connected to a manometer and the reagents are mixed with a motor-driven stirrer. The position of the reagents in the test tube permits the continuous measurement of oxygen evolution from the time of mixing, without the need to stop the reaction by the addition of acid after each incubation time. The enzyme activity is reported as KHb, i.e., mg hydrogen peroxide decomposed per second per gram of hemoglobin (s-1 g Hb-1. The value obtained for catalase activity in 28 samples of hemolyzed human blood was 94.4 ± 6.17 mg H2O2 s-1 g Hb-1. The results obtained were precise and consistent, indicating that this rapid, simple and inexpensive method could be useful for research and routine work.

  9. pH dependence of cyanide binding to the ferric heme domain of the direct oxygen sensor from Escherichia coli and the effect of alkaline denaturation.

    Science.gov (United States)

    Bidwai, Anil K; Ok, Esther Y; Erman, James E

    2008-09-30

    The spectrum of the ferric heme domain of the direct oxygen sensor protein from Escherichia coli ( EcDosH) has been measured between pH 3.0 and 12.6. EcDosH undergoes acid denaturation with an apparent p K a of 4.24 +/- 0.05 and a Hill coefficient of 3.1 +/- 0.6 and reversible alkaline denaturation with a p K a of 9.86 +/- 0.04 and a Hill coefficient of 1.1 +/- 0.1. Cyanide binding to EcDosH has been investigated between pH 4 and 11. The EcDosH-cyanide complex is most stable at pH 9 with a K D of 0.29 +/- 0.06 microM. The kinetics of cyanide binding are monophasic between pH 4 and 8. At pH >or=8.5, the reaction is biphasic with the fast phase dependent upon the cyanide concentration and the slow phase independent of cyanide. The slow phase is attributed to conversion of denatured EcDosH to the native state, with a pH-independent rate of 0.052 +/- 0.006 s (-1). The apparent association rate constant for cyanide binding to EcDosH increases from 3.6 +/- 0.1 M (-1) s (-1) at pH 4 to 520 +/- 20 M (-1) s (-1) at pH 11. The dissociation rate constant averages (8.6 +/- 1.3) x 10 (-5) s (-1) between pH 5 and 9, increasing to (1.4 +/- 0.1) x 10 (-3) s (-1) at pH 4 and (2.5 +/- 0.1) x 10 (-3) s (-1) at pH 12.2. The mechanism of cyanide binding is consistent with preferential binding of the cyanide anion to native EcDosH. The reactions of imidazole and H 2O 2 with ferric EcDosH were also investigated and show little reactivity.

  10. P-gp expression in brown trout erythrocytes: evidence of a detoxification mechanism in fish erythrocytes.

    Science.gov (United States)

    Valton, Emeline; Amblard, Christian; Wawrzyniak, Ivan; Penault-Llorca, Frederique; Bamdad, Mahchid

    2013-12-05

    Blood is a site of physiological transport for a great variety of molecules, including xenobiotics. Blood cells in aquatic vertebrates, such as fish, are directly exposed to aquatic pollution. P-gp are ubiquitous "membrane detoxification proteins" implicated in the cellular efflux of various xenobiotics, such as polycyclic aromatic hydrocarbons (PAHs), which may be pollutants. The existence of this P-gp detoxification system inducible by benzo [a] pyrene (BaP), a highly cytotoxic PAH, was investigated in the nucleated erythrocytes of brown trout. Western blot analysis showed the expression of a 140-kDa P-gp in trout erythrocytes. Primary cultures of erythrocytes exposed to increasing concentrations of BaP showed no evidence of cell toxicity. Yet, in the same BaP-treated erythrocytes, P-gp expression increased significantly in a dose-dependent manner. Brown trout P-gp erythrocytes act as membrane defence mechanism against the pollutant, a property that can be exploited for future biomarker development to monitor water quality.

  11. The mechanism of erythrocyte sedimentation. Part 2: The global collapse of settling erythrocyte network.

    Science.gov (United States)

    Pribush, A; Meyerstein, D; Meyerstein, N

    2010-01-01

    Results reported in the companion paper showed that erythrocytes in quiescent blood are combined into a network followed by the formation of plasma channels within it. This study is focused on structural changes in the settling dispersed phase subsequent to the channeling and the effect of the structural organization on the sedimentation rate. It is suggested that the initial, slow stage of erythrocyte sedimentation is mainly controlled by the gravitational compactness of the collapsed network. The lifetime of RBC network and hence the duration of the slow regime of erythrocyte sedimentation decrease with an increase in the intercellular pair potential and with a decrease in Hct. The gravitational compactness of the collapsed network causes its rupture into individual fragments. The catastrophic collapse of the network transforms erythrocyte sedimentation from slow to fast regime. The size of RBC network fragment is insignificantly affected by Hct and is mainly determined by the intensity of intercellular attractive interactions. When cells were suspended in the weak aggregating medium, the Stokes radius of fragments does not differ measurably from that of individual RBCs. The proposed mechanism provides a reasonable explanation of the effects of RBC aggregation, Hct and the initial height of the blood column on the delayed erythrocyte sedimentation.

  12. Triggering of Suicidal Erythrocyte Death by Regorafenib

    Directory of Open Access Journals (Sweden)

    Jens Zierle

    2016-01-01

    Full Text Available Background/Aims: The multikinase inhibitor regorafenib is utilized for the treatment of malignancy. The substance is effective in part by triggering suicidal death or apoptosis of tumor cells. Side effects of regorafenib include anemia. At least in theory, regorafenib induced anemia could result from stimulated suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and ceramide. The present study explored, whether regorafenib induces eryptosis and, if so, whether it is effective up- and/or downstream of Ca2+. Methods: To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to regorafenib (≥ 0.5 µg/ml significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter (≥ 1.25 µg/ml, but did not significantly increase Fluo3-fluorescence, DCFDA fluorescence or ceramide abundance. The effect of regorafenib on annexin-V-binding and forward scatter was not significantly blunted by removal of extracellular Ca2+. Regorafenib (5 µg/ml significantly augmented the increase of annexin-V-binding, but significantly blunted the decrease of forward scatter following treatment with the Ca2+ ionophore ionomycin. Conclusions: Regorafenib triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part downstream of Ca2+.

  13. Triggering of Suicidal Erythrocyte Death by Regorafenib.

    Science.gov (United States)

    Zierle, Jens; Bissinger, Rosi; Bouguerra, Ghada; Abbès, Salem; Lang, Florian

    2016-01-01

    The multikinase inhibitor regorafenib is utilized for the treatment of malignancy. The substance is effective in part by triggering suicidal death or apoptosis of tumor cells. Side effects of regorafenib include anemia. At least in theory, regorafenib induced anemia could result from stimulated suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide. The present study explored, whether regorafenib induces eryptosis and, if so, whether it is effective up- and/or downstream of Ca2+. To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. A 48 hours exposure of human erythrocytes to regorafenib (≥ 0.5 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter (≥ 1.25 µg/ml), but did not significantly increase Fluo3-fluorescence, DCFDA fluorescence or ceramide abundance. The effect of regorafenib on annexin-V-binding and forward scatter was not significantly blunted by removal of extracellular Ca2+. Regorafenib (5 µg/ml) significantly augmented the increase of annexin-V-binding, but significantly blunted the decrease of forward scatter following treatment with the Ca2+ ionophore ionomycin. Regorafenib triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part downstream of Ca2+. © 2016 The Author(s) Published by S. Karger AG, Basel.

  14. Stimulation of Suicidal Erythrocyte Death by Garcinol

    Directory of Open Access Journals (Sweden)

    Antonella Fazio

    2015-09-01

    Full Text Available Background/Aims: The benzophenone garcinol from dried fruit rind of Garcinia indica counteracts malignancy, an effect at least in part due to stimulation of apoptosis. The proapototic effect of garcinol is attributed in part to inhibition of histone acetyltransferases and thus modification of gene expression. Moreover, garcinol triggers mitochondrial depolarisation. Erythrocytes lack gene expression and mitochondria but are nevertheless able to enter apoptosis-like suicidal death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include oxidative stress, energy depletion and Ca2+ entry with increase of cytosolic Ca2+ activity ([Ca2+]i. The present study explored, whether and how garcinol induces eryptosis. Methods: To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence and cytosolic ATP levels utilizing a luciferin-luciferase-based assay. Results: A 24 hours exposure of human erythrocytes to garcinol (2.5 or 5 µM significantly increased the percentage of annexin-V-binding cells. Garcinol decreased (at 1 µM and 2.5 µM or increased (at 5 µM forward scatter. Garcinol (5 µM further increased Fluo3-fluorescence, increased DCFDA fluorescence, and decreased cytosolic ATP levels. The effect of garcinol on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+. Conclusions: Garcinol triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to stimulation of ROS formation, energy depletion and Ca2+ entry.

  15. Induction of Suicidal Erythrocyte Death by Novobiocin

    Directory of Open Access Journals (Sweden)

    Adrian Lupescu

    2014-03-01

    Full Text Available Background: Novobiocin, an aminocoumarin antibiotic, interferes with heat shock protein 90 and hypoxia inducible factor dependent gene expression and thus compromises cell survival. Similar to survival of nucleated cells, erythrocyte survival could be disrupted by eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and by phospholipd scrambling of the cell membrane with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i. The Ca2+ sensitivity of phospholipid scrambling is enhanced by ceramide. The present study explored, whether novobiocin elicits eryptosis. Methods: [Ca2+]i was estimated from Fluo3-fluorescence, ceramide abundance utilizing fluorescent antibodies, cell volume from forward scatter, phosphatidylserine-exposure from annexin V binding. Results: A 48 hours exposure to novobiocin (500 µM was followed by a significant increase of [Ca2+]i, decrease of forward scatter, increase of annexin-V-binding and enhanced ceramide formation. Removal of extracellular Ca2+ virtually abrogated the increase of annexin-V-binding following novobiocin exposure. Conclusions: Novobiocin stimulates eryptosis, an effect at least in part due to entry of extracellular Ca2+ and formation of ceramide.

  16. 31P-NMR measurements of ATP, ADP, 2,3-diphosphoglycerate and Mg2+ in human erythrocytes.

    Science.gov (United States)

    Petersen, A; Kristensen, S R; Jacobsen, J P; Hørder, M

    1990-08-17

    Absolute 31P-NMR measurements of ATP, ADP and 2,3-diphosphoglycerate (2,3-DPG) in oxygenated and partly deoxygenated human erythrocytes, compared to measurements by standard assays after acid extraction, show that ATP is only 65% NMR visible, ADP measured by NMR is unexpectedly 400% higher than the enzymatic measurement and 2,3-DPG is fully NMR visible, regardless of the degree of oxygenation. These results show that binding to hemoglobin is unlikely to cause the decreased visibility of ATP in human erythrocytes as deoxyhemoglobin binds the phosphorylated metabolites more tightly than oxyhemoglobin. The high ADP visibility is unexplained. The levels of free Mg2+ [( Mg2+]free) in human erythrocytes are 225 mumol/l at an oxygen saturation of 98.6% and instead of the expected increase, the level decreased to 196 mumol/l at an oxygen saturation of 38.1% based on the separation between the alpha- and beta-ATP peaks. [Mg2+]free in the erythrocytes decreased to 104 mumol/l at a high 2,3-DPG concentration of 25.4 mmol/l red blood cells (RBC) and a normal ATP concentration of 2.05 mmol/l RBC. By increasing the ATP concentration to 3.57 mmol/l RBC, and with a high 2,3-DPG concentration of 24.7 mmol/l RBC, the 31P-NMR measured [Mg2+]free decreased to 61 mumol/l. These results indicate, that the 31P-NMR determined [Mg2+]free in human erythrocytes, based solely on the separation of the alpha- and beta-ATP peaks, does not give a true measure of intracellular free Mg2+ changes with different oxygen saturation levels. Furthermore the measurement is influenced by the concentration of the Mg2+ binding metabolites ATP and 2,3-DPG. Failure to take these factors into account when interpreting 31P-NMR data from human erythrocytes may explain some discrepancies in the literature regarding [Mg2+]free.

  17. Subcutaneous administration of carrier erythrocytes: slow release of entrapped agent

    International Nuclear Information System (INIS)

    DeLoach, J.R.; Corrier, D.E.

    1988-01-01

    Carrier erythrocytes administered subcutaneously in mice release encapsulated molecules at the injection site and through cells that escape the injection site. One day postinjection, the efflux of encapsulated [ 14 C]sucrose, [ 3 H]inulin, and 51 Cr-hemoglobin from the injection site was 45, 55, and 65%, respectively. Intact carrier erythrocytes escaped the injection site and entered the blood circulation carrying with them the encapsulated molecules. Most of the encapsulated [ 3 H]inulin that reached whole blood circulated within erythrocytes. Small but measurable numbers of encapsulated molecules were trapped within lymph nodes. Subcutaneous injection of carrier erythrocytes may allow for limited extravascular tissue targeting of drugs

  18. Hepatic or splenic targeting of carrier erythrocytes: a murine model

    International Nuclear Information System (INIS)

    Zocchi, E.; Guida, L.; Benatti, U.; Canepa, M.; Borgiani, L.; Zanin, T.; De Flora, A.

    1987-01-01

    Carrier mouse erythrocytes, i.e., red cells, subjected to a dialysis technique involving transient hypotonic hemolysis and isotonic resealing were treated in vitro in three different ways: (a) energy depletion by exposure for 90 min at 42 degrees C; (b) desialylation by incubation with neuroaminidase; and (c) oxidative stress by incubation with H 2 O 2 and NaN3. Procedure (c) afforded maximal damage, as shown by analysis of biochemical properties of the treated erythrocytes. Reinfusion in mice of the variously manipulated erythrocytes following their 51 Cr labeling showed extensive fragilization as indicated by rapid clearance of radioactivity from the circulation. Moreover, both the energy-depleted and the neuraminidase-treated erythrocytes showed a preferential liver uptake, reaching 50 and 75%, respectively, within 2 h. On the other hand, exposure of erythrocytes to the oxidant stress triggered a largely splenic removal, accounting for almost 40% of the reinjected cells within 4 h. Transmission electron microscopy of liver from mice receiving energy-depleted erythrocytes demonstrated remarkable erythrocyte congestion within the sinusoids, followed by hyperactivity of Kupffer cells and by subsequent thickening of the perisinusoidal Disse space. Concomitantly, levels of serum transaminase activities were moderately increased. Each of the three procedures of manipulation of carrier erythrocytes may prove applicable under conditions where selective targeting of erythrocyte-encapsulated chemicals and drugs to either the liver or the spleen has to be achieved

  19. Synergistic Effect of Rapamycin and Metformin Against Age-Dependent Oxidative Stress in Rat Erythrocytes.

    Science.gov (United States)

    Singh, Abhishek Kumar; Garg, Geetika; Singh, Sandeep; Rizvi, Syed Ibrahim

    2017-10-01

    Erythrocytes are particularly vulnerable toward age-dependent oxidative stress-mediated damage. Caloric restriction mimetics (CRMs) may provide a novel strategy for the maintenance of redox balance as well as effective treatment of age-associated diseases. Herein, we have investigated the beneficial effect of cotreatment with CRM-candidate drugs, rapamycin (an immunosuppressant drug and inhibitor of mammalian target of rapamycin) and metformin (an antidiabetic biguanide and activator of adenosine monophosphate kinase), against aging-induced oxidative stress in erythrocytes and plasma of aging rats. Male Wistar rats of age 4 (young) and 24 months (old) were coexposed to rapamycin (0.5 mg/kg body weight [b.w.]) and metformin (300 mg/kg b.w.), and data were compared with the response of rats receiving an independent exposure to these chemicals at similar doses. The exposure of individual candidate drugs significantly reversed the age-dependent alterations in the endpoints associated with oxidative stress such as reactive oxygen species, ferric reducing ability of plasma, malondialdehyde, reduced glutathione, plasma membrane redox system, plasma protein carbonyl, and acetyl cholinesterase in erythrocytes and plasma of aging rats. However, the cotreatment with rapamycin and metformin showed a significant augmented effect compared with individual drug interventions on reversal of these age-dependent biomarkers of oxidative stress, suggesting a synergistic response. Thus, the findings open up further possibilities for the design of new combinatorial therapies to prevent oxidative stress- and age-associated health problems.

  20. Metallic mercury uptake by catalase Part 1 In Vitro metallic mercury uptake by various kind of animals' erythrocytes and purified human erythrocyte catalase

    OpenAIRE

    劒持,堅志

    1980-01-01

    The uptake of metallic mercury was studied using erythrocytes with different catalase activities taken from various kind of animals. The results were: 1) The uptake of metallic mercury by erythrocytes paralleled the activity of catalase in the erythrocytes with and without hydrogen peroxide, suggesting that the erythrocyte catalase activity is related to the uptake of metallic mercury. 2) The uptake of metallic mercury occurred not only with purified human erythrocyte catalase but also with h...

  1. Plasmodium falciparum secretome in erythrocyte and beyond

    Directory of Open Access Journals (Sweden)

    Rani eSoni

    2016-02-01

    Full Text Available Plasmodium falciparum is the causative agent of deadly malaria disease. It is an intracellular eukaryote and completes its multi-stage life cycle spanning the two hosts viz, mosquito and human. In order to habituate within host environment, parasite conform several strategies to evade host immune responses such as surface antigen polymorphism or modulation of host immune system and it is mediated by secretion of proteins from parasite to the host erythrocyte and beyond, collectively known as, malaria secretome. In this review, we will discuss about the deployment of parasitic secretory protein in mechanism implicated for immune evasion, protein trafficking, providing virulence, changing permeability and cyto-adherence of infected erythrocyte. We will be covering the possibilities of developing malaria secretome as a drug/vaccine target. This gathered information will be worthwhile in depicting a well-organized picture for host-pathogen interplay during the malaria infection and may also provide some clues for development of novel anti-malarial therapies.

  2. The role of the erythrocyte in antitumour drug transport

    NARCIS (Netherlands)

    Dumez, Herlinde

    2005-01-01

    The area of research on the substance-carrier capacity of the erythrocyte is rather limited and it remains difficult to estimate the impact of erythrocyte drug level monitoring in the clinic. Although equilibrium between blood and tissues based on the dissolution of compounds in the plasma water

  3. Transcriptomic Analysis of Young and Old Erythrocytes of Fish

    Directory of Open Access Journals (Sweden)

    Miriam Götting

    2017-12-01

    Full Text Available Understanding gene expression changes over the lifespan of cells is of fundamental interest and gives important insights into processes related to maturation and aging. This study was undertaken to understand the global transcriptome changes associated with aging in fish erythrocytes. Fish erythrocytes retain their nuclei throughout their lifetime and they are transcriptionally and translationally active. However, they lose important functions during their lifespan in the circulation. We separated rainbow trout (Oncorhynchus mykiss erythrocytes into young and old fractions using fixed angle-centrifugation and analyzed transcriptome changes using RNA sequencing (RNA-seq technology and quantitative real-time PCR. We found 930 differentially expressed between young and old erythrocyte fractions; 889 of these showed higher transcript levels in young, while only 34 protein-coding genes had higher transcript levels in old erythrocytes. In particular genes involved in ion binding, signal transduction, membrane transport, and those encoding various enzyme classes are affected in old erythrocytes. The transcripts with higher levels in old erythrocytes were associated with seven different GO terms within biological processes and nine within molecular functions and cellular components, respectively. Our study furthermore found several highly abundant transcripts as well as a number of differentially expressed genes (DEGs for which the protein products are currently not known revealing the gaps of knowledge in most non-mammalian vertebrates. Our data provide the first insight into changes involved in aging on the transcriptional level and thus opens new perspectives for the study of maturation processes in fish erythrocytes.

  4. The Role and Mechanism of Erythrocyte Invasion by Francisella tularensis

    Directory of Open Access Journals (Sweden)

    Deanna M. Schmitt

    2017-05-01

    Full Text Available Francisella tularensis is an extremely virulent bacterium that can be transmitted naturally by blood sucking arthropods. During mammalian infection, F. tularensis infects numerous types of host cells, including erythrocytes. As erythrocytes do not undergo phagocytosis or endocytosis, it remains unknown how F. tularensis invades these cells. Furthermore, the consequence of inhabiting the intracellular space of red blood cells (RBCs has not been determined. Here, we provide evidence indicating that residing within an erythrocyte enhances the ability of F. tularensis to colonize ticks following a blood meal. Erythrocyte residence protected F. tularensis from a low pH environment similar to that of gut cells of a feeding tick. Mechanistic studies revealed that the F. tularensis type VI secretion system (T6SS was required for erythrocyte invasion as mutation of mglA (a transcriptional regulator of T6SS genes, dotU, or iglC (two genes encoding T6SS machinery severely diminished bacterial entry into RBCs. Invasion was also inhibited upon treatment of erythrocytes with venom from the Blue-bellied black snake (Pseudechis guttatus, which aggregates spectrin in the cytoskeleton, but not inhibitors of actin polymerization and depolymerization. These data suggest that erythrocyte invasion by F. tularensis is dependent on spectrin utilization which is likely mediated by effectors delivered through the T6SS. Our results begin to elucidate the mechanism of a unique biological process facilitated by F. tularensis to invade erythrocytes, allowing for enhanced colonization of ticks.

  5. Desickling of Sickle Cell Erythrocytes by Pulsed RF Fields.

    Science.gov (United States)

    1986-09-16

    spectrophotometery. Field induced menbrane potential which causes the L partyl breakdown of the memrbrane and the formation of pores was calculated... plasma . Fig.5 shows the photographs of sickled and desickled SS erythrocytes which are suspended in Hank’s solution. As shown, desickled erythrocytes

  6. Paired Chicken and Mammalian Erythrocyte Indicator Systems for ...

    African Journals Online (AJOL)

    A retrospective flock health analysis revealed that the higher titres were associated with confirmable Newcastle Disease (ND) outbreaks in the affected flocks. These findings therefore suggested that the use of standardised guinea pig erythrocytes in parallel with chicken erythrocytes as indicators, might facilitate field ND ...

  7. 21 CFR 864.6700 - Erythrocyte sedimentation rate test.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Erythrocyte sedimentation rate test. 864.6700 Section 864.6700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6700 Erythrocyte...

  8. Erythrocyte metallothionein as an index of zinc status in humans

    International Nuclear Information System (INIS)

    Grider, A.; Bailey, L.B.; Cousins, R.J.

    1990-01-01

    Metallothionein concentrations in erythrocyte lysates derived from human subjects were measured by an ELISA procedure. IgG obtained from serum of sheep injected with human metallothionein 1 was used in this competitive assay. Subjects were fed a semipurified zinc-deficient diet for an 8-day depletion period after 3 days of acclimation. Fasting plasma zinc concentrations were reduced ∼7%. Metallothionein in the erythrocyte lysates was significantly decreased to 59% of the initial level by the end of the depletion period. Supplementation of these depleted subjects with zinc did not increase erythrocyte metallothionein levels within 24 hr. Daily supplementation of control subjects with zinc increased erythrocyte metallothionein to a 7-fold maximum within 7 days. These levels were reduced by 61% within 14 days after zinc supplementation was terminated. Incubation of rat [ 35 S]metallothionein with human erythrocyte lysate showed a time-dependent increase in 35 S soluble in 20% trichloroacetic acid, indicating degradation of the labeled protein, presumably via protease activity in the lysate. It is proposed that zinc supplementation induces erythrocyte metallothionein during erythropoiesis and that low zinc intake decreases synthesis and/or accelerates degradation of the protein in reticulocytes/erythrocytes. Metallothionein levels in erythrocytes may provide a useful index upon which to assess zinc status in humans

  9. Ferrokinetic and erythrocyte survival studies in healthy and anemic cats

    Energy Technology Data Exchange (ETDEWEB)

    Madewell, B.R.; Holmes, P.H.; Onions, D.E.

    1983-03-01

    Erythrocyte survival and ferrokinetic studies were adapted to the cat. For 5 clinically healthy 4- to 9-month-old cats, mean /sup 51/Cr-labeled erythrocyte survival was 144 hours, and mean plasma /sup 59/Fe-labeled transferrin disappearance halftime was 51 minutes. Erythrocyte use of radioiron was rapid and efficient, with 50% to 80% of labeled iron incorporated into the erythron by 100 hours after injection into the cat. Six cats with feline leukemia virus infection were studied. For 2 cats with erythroid aplasia associated with C subgroup of feline leukemia virus, erythrocyte survival times were similar to those determined for the healthy cats, but plasma radioiron disappearance half time and erythrocyte use of radioiron were markedly diminished.

  10. Ferrokinetic and erythrocyte survival studies in healthy and anemic cats

    International Nuclear Information System (INIS)

    Madewell, B.R.; Holmes, P.H.; Onions, D.E.

    1983-01-01

    Erythrocyte survival and ferrokinetic studies were adapted to the cat. For 5 clinically healthy 4- to 9-month-old cats, mean 51 Cr-labeled erythrocyte survival was 144 hours, and mean plasma 59 Fe-labeled transferrin disappearance halftime was 51 minutes. Erythrocyte use of radioiron was rapid and efficient, with 50% to 80% of labeled iron incorporated into the erythron by 100 hours after injection into the cat. Six cats with feline leukemia virus infection were studied. For 2 cats with erythroid aplasia associated with C subgroup of feline leukemia virus, erythrocyte survival times were similar to those determined for the healthy cats, but plasma radioiron disappearance half time and erythrocyte use of radioiron were markedly diminished

  11. Silica Aerogels Doped with Ru(II) Tris 1,l0-Phenanthro1ine)-Electron Acceptor Dyads: Improving the Dynamic Range, Sensitivity and Response Time of Sol-Gel Based Oxygen Sensors

    Science.gov (United States)

    Kevebtusm Bucgikas; Rawashdeh, Abdel M.; Elder, Ian A.; Yang, Jinhua; Dass, Amala; Sotiriou-Leventis, Chariklia

    2005-01-01

    Complexes 1 and 2 were characterized in fluid and frozen solution and as dopants of silica aerogels. The intramolecular quenching efficiency of pendant 4-benzoyl-N-methylpyridinium group (4BzPy) is solvent dependent: emission is quenched completely in acetonitrile but not in alcohols. On the other hand, N-benzyl-N'-methylviologen (BzMeV) quenches the emission in all solvents completely. The differences are traced electrochemically to a stronger solvation effect by the alcohol in the case of 1. In fiozen matrices or absorbed on the surfaces of silica aerogel, both 1 and 2 are photoluminescent. The lack of quenching has been traced to the environmental rigidity. When doped aerogels are cooled to 77K, the emission shifts to the blue and its intensity increases in analogy to what is observed with Ru(II) complexes in media undergoing fluid-to-rigid transition. The photoluminescence of 1 and 2 from the aerogel is quenched by oxygen diffusing through the pores. In the presence of oxygen, aerogels doped with 1 can modulate their emission over a wider dynamic range than aerogels doped with 2, and both are more sensitive than aerogels doped with Ru(II) tris(1,l0- phenanthroline). In contrast to frozen solutions, the luminescent moieties in the bulk of aerogels kept at 77K are still accessible, leading to more sensitive platforms for oxygen sensors than other ambient temperature configurations.

  12. Sickle erythrocytes inhibit human endothelial cell DNA synthesis

    International Nuclear Information System (INIS)

    Weinstein, R.; Zhou, M.A.; Bartlett-Pandite, A.; Wenc, K.

    1990-01-01

    Patients with sickle cell anemia experience severe vascular occlusive phenomena including acute pain crisis and cerebral infarction. Obstruction occurs at both the microvascular and the arterial level, and the clinical presentation of vascular events is heterogeneous, suggesting a complex etiology. Interaction between sickle erythrocytes and the endothelium may contribute to vascular occlusion due to alteration of endothelial function. To investigate this hypothesis, human vascular endothelial cells were overlaid with sickle or normal erythrocytes and stimulated to synthesize DNA. The erythrocytes were sedimented onto replicate monolayers by centrifugation for 10 minutes at 17 g to insure contact with the endothelial cells. Incorporation of 3H-thymidine into endothelial cell DNA was markedly inhibited during contact with sickle erythrocytes. This inhibitory effect was enhanced more than twofold when autologous sickle plasma was present during endothelial cell labeling. Normal erythrocytes, with or without autologous plasma, had a modest effect on endothelial cell DNA synthesis. When sickle erythrocytes in autologous sickle plasma were applied to endothelial monolayers for 1 minute, 10 minutes, or 1 hour and then removed, subsequent DNA synthesis by the endothelial cells was inhibited by 30% to 40%. Although adherence of sickle erythrocytes to the endothelial monolayers was observed under these experimental conditions, the effect of sickle erythrocytes on endothelial DNA synthesis occurred in the absence of significant adherence. Hence, human endothelial cell DNA synthesis is partially inhibited by contact with sickle erythrocytes. The inhibitory effect of sickle erythrocytes occurs during a brief (1 minute) contact with the endothelial monolayers, and persists for at least 6 hours of 3H-thymidine labeling

  13. Development of antifouling of electrochemical solid-state dissolved oxygen sensors based on nanostructured Cu0.4Ru3.4O7 + RuO2 sensing electrodes

    International Nuclear Information System (INIS)

    Zhuiykov, Serge; Kalantar-zadeh, Kourosh

    2012-01-01

    Tailoring nanostructured sensing electrode materials to high antifouling resistance has been one of the main priorities of the development of water quality sensors in the 21st century. Nanostructured Cu 0.4 Ru 3.4 O 7 + RuO 2 -SEs have been developed to address the bio-fouling problem. The change in Cu 0.4 Ru 3.4 O 7 + RuO 2 structural development being promoted by advances in nano- and micro-scale pattering. Nanostructured Cu 0.4 Ru 3.4 O 7 + RuO 2 -SEs with different mol% of Cu 2 O were screen-printed on alumina sensor substrates and were consequently subjected to a 3-month field trial at the Water Treatment Plant. Their structural and electrochemical properties before and after the experiment were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical cyclic voltammerty (CV) techniques. The relationship between dissolved oxygen (DO) and the sensor's potential difference was found to be relatively linear, with the maximum sensitivity of −46 mV per decade being achieved at 20 mol% Cu 2 O at 7.27 pH. Moreover, a 3-month field trial in the sewerage environment has shown that Cu 0.4 Ru 3.4 O 7 + RuO 2 -SE with 20 mol% of Cu 2 O possesses much higher defences against bio-fouling than the same SE with only 10 mol% of Cu 2 O. The super-hydrophobic property of the developed Cu 0.4 Ru 3.4 O 7 + RuO 2 complex oxide has been considered as one of the essential pre-requisites for high antifouling resistance. Multiple antifouling defence strategies from biomimetic to bio-inspired must be incorporated in further development of nanostructured oxide SE to solve problems of bio-fouling on the sensor's SE.

  14. Erythrocyte 22Na+ influx in hypertension

    International Nuclear Information System (INIS)

    Shalev, O.; Eaton, J.W.; Ben-Ishay, D.

    1984-01-01

    We assessed 22Na+ uptake by erythrocytes (RBC) from 38 individuals with essential hypertension and 37 healthy controls. All subjects were male, white, non-obese and with normal renal function, obviating sex, race, hormonal, ponderal and renal factors known to influence RBC Na+ handling. The mean +/- sem 22Na+ uptake of the patients was 284 +/- 16 mumole/liter RBC/hour while that of normal controls was 249 +/- 11 mumole/liter RBC/hour; although the difference reached borderline significance, individual values showed considerable overlap. Consequently, in our population, RBC 22Na+ uptake is not a reliable marker for essential hypertension. We believe that previous studies should be reassessed with regard to patients' characteristics and future studies employ rigorous criteria in selection of subjects

  15. Fluorescence energy transfer on erythrocyte membranes

    International Nuclear Information System (INIS)

    Fuchs, H.M.; Hof, M.; Lawaczeck, R.

    1995-08-01

    Stationary and time-dependent fluorescence have been measured for a donor/acceptor (DA) pair bound to membrane proteins of bovine erythrocyte ghosts. The donor N-(p-(2-benzoxazolyl)phenyl)-maleimid (BMI) and the acceptor fluram bind to SH- and NH 2 -residues, respectively. The fluorescence spectra and the time-dependent emission are consistent with a radiationless fluorescence energy transfer (RET). The density of RET-effective acceptor binding sites c=0.072 nm -2 was calculated on the basis of the two-dimensional Foerster-kinetic. Band3 protein is the only membrane spanning protein with accessible SH-groups, and therefore only effective binding sites on the band3 protein are counted for the RET measurements performed. (author). 23 refs, 4 figs, 2 tabs

  16. In Vitro Protective Effect of Phikud Navakot Extraction on Erythrocyte

    Directory of Open Access Journals (Sweden)

    Kanchana Kengkoom

    2016-01-01

    Full Text Available Phikud Navakot (PN, Thai herbal remedy in National List of Essential Medicines, has been claimed to reduce many cardiovascular symptoms especially dizziness and fainting. Apart from blood supply, erythrocyte morphology, in both shape and size, is one of the main consideration factors in cardiovascular diseases and may be affected by vascular oxidative stress. However, little is known about antioxidative property of PN on erythrocyte to preserve red blood cell integrity. In this study, 1,000 μM hydrogen peroxide-induced oxidative stress was conducted on sheep erythrocyte. Three doses of PN (1, 0.5, and 0.25 mg/mL and 10 μM of ascorbic acid were compared. The released hemoglobin absorbance was measured to demonstrate hemolysis. Electron microscopic and immunohistochemical studies were also performed to characterize dysmorphic erythrocyte and osmotic ability in relation to aquaporin- (AQP- 1 expression, respectively. The results revealed that all doses of PN and ascorbic acid decreased the severity of dysmorphic erythrocyte, particularly echinocyte, acanthocyte, knizocyte, codocyte, clumping, and other malformations. However, the most effective was 0.5 mg/mL PN dosage. In addition, hydrostatic pressure may be increased in dysmorphic erythrocyte in association with AQP-1 upregulation. Our results demonstrated that PN composes antioxidative effect to maintain the integrity and osmotic ability on sheep erythrocyte.

  17. Deformability of Erythrocytes and Oxidative Damage in Alzheimer Disease

    Directory of Open Access Journals (Sweden)

    Mukerrem Betul Yerer

    2012-04-01

    Full Text Available Purpose: A lowered cerebral perfusion as a consequence of hemodynamic microcirculatory insufficiency is one of the factors underlying in Alzheimer's disease, which is a neurodegenerative disorder leading to progressive cognitive impairment. Erythrocyte deformability is one of the major factors affecting the microcirculatory hemodynamics which is closely related to the oxidative damage. The aim of this study is to investigate the relationship between the erythrocyte deformability, nitric oxide levels and oxidative stress in Alzheimer's disease. Methods: The blood samples of 30 elderly people in three groups consisting of healthy control and different severities of the disease (low and severe were used. Then the erythrocytes were isolated and the deformability of erythrocytes was determined by Rheodyne SSD evaluating the elongation indexes of the erythrocytes under different shear stress. The catalase, glutathione peroxidase and plasma nitric oxide levels were measured spectrophotometric ally. Results: The plasma nitric oxide levels, catalase activities were found significantly higher and glutathione peroxidase activity was significantly lower in severe Alzheimer's disease patients compared to the control group. However, the deformability of erythrocytes was not significantly affected from these alterations. Conclusion: the oxidant-antioxidant status is dramatically changed in Alzheimer's disease patients with the severity of the disease and similar alterations were seen in the nitric oxide levels without any significant change in erythrocyte deformability. [Cukurova Med J 2012; 37(2.000: 65-75

  18. Amperometric glucose sensor based on enhanced catalytic reduction of oxygen using glucose oxidase adsorbed onto core-shell Fe3O4-silica-Au magnetic nanoparticles

    International Nuclear Information System (INIS)

    Wang Aijun; Li Yongfang; Li Zhonghua; Feng Jiuju; Sun Yanli; Chen Jianrong

    2012-01-01

    Monodisperse Fe 3 O 4 magnetic nanoparticles (NPs) were prepared under facile solvothermal conditions and successively functionalized with silica and Au to form core/shell Fe 3 O 4 -silica-Au NPs. Furthermore, the samples were used as matrix to construct a glucose sensor based on glucose oxidase (GOD). The immobilized GOD retained its bioactivity with high protein load of 3.92 × 10 −9 mol·cm −2 , and exhibited a surface-controlled quasi-reversible redox reaction, with a fast heterogeneous electron transfer rate of 7.98 ± 0.6 s −1 . The glucose biosensor showed a broad linear range up to 3.97 mM with high sensitivity of 62.45 μA·mM −1 cm −2 and fast response (less than 5 s). - Graphical abstract: Core-shell structured Fe 3 O 4 -silica-Au nanoparticles were prepared and used as matrix to construct an amperometric glucose sensor based on glucose oxidase, which showed broad linear range, high sensitivity, and fast response. Highlights: ► Synthesis of monodispersed Fe 3 O 4 nanoparticles. ► Fabrication of core/shell Fe 3 O 4 -silica-Au nanoparticles. ► Construction of a novel glucose sensor with wide linear range, high sensitivity and fast response.

  19. Dietary indicaxanthin from cactus pear (Opuntia ficus-indica L. Mill) fruit prevents eryptosis induced by oxysterols in a hypercholesterolaemia-relevant proportion and adhesion of human erythrocytes to endothelial cell layers.

    Science.gov (United States)

    Tesoriere, Luisa; Attanzio, Alessandro; Allegra, Mario; Livrea, Maria A

    2015-08-14

    Toxic oxysterols in a hypercholesterolaemia-relevant proportion cause suicidal death of human erythrocytes or eryptosis. This process proceeds through early production of reactive oxygen species (ROS), release of prostaglandin (PGE2) and opening of PGE2-dependent Ca channels, membrane phosphatidylserine (PS) externalisation, and cell shrinkage. The present study was the first to reveal that a bioavailable phytochemical, indicaxanthin (Ind) from cactus pear fruit, in a concentration range (1.0-5.0 μM) consistent with its plasma level after a fruit meal, prevents PS externalisation and cell shrinkage in a dose-dependent manner when incubated with isolated healthy human erythrocytes exposed to an oxysterol mixture for 48 h. Dietary Ind inhibited ROS production, glutathione (GSH) depletion, PGE2 release and Ca2+ entry. Ind alone did not modify the erythrocyte redox environment or affect other parameters. Ex vivo spiking of normal human blood with the oxysterol mixture for 48 h induced eryptosis, resulting in the production of ROS and decreased levels of GSH, which was prevented by concurrent exposure to 5 μm-Ind. The adherence of eryptotic erythrocytes to the endothelium causes vascular tissue injury. Erythrocytes isolated from blood incubated with the oxysterol mixture plus 5 μm-Ind did not adhere to endothelial cell monolayers. Eryptotic erythrocytes may contribute to thrombotic complications in hypercholesterolaemia. Our findings suggest the positive effects of diets containing Ind on erythrocytes in hypercholesterolaemic subjects.

  20. The Uremic Toxin Acrolein Promotes Suicidal Erythrocyte Death

    Directory of Open Access Journals (Sweden)

    Mohamed Siyabeldin E. Ahmed

    2013-05-01

    Full Text Available Background: Anemia is a major complication of end stage renal disease. The anemia is mainly the result of impaired formation of erythrocytes due to lack of erythropoietin and iron deficiency. Compelling evidence, however, points to the contribution of accelerated erythrocyte death, which decreases the life span of circulating erythrocytes. Erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine-exposure at the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i. Erythrocytes could be sensitized to cytosolic Ca2+ by ceramide. In end stage renal disease, eryptosis may possibly be stimulated by uremic toxins. The present study explored, whether the uremic toxin acrolein could trigger eryptosis. Methods: Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin-V-binding, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, and ceramide from fluorescent antibodies. Results: A 48 h exposure to acrolein (30 - 50 µM did not significantly modify [Ca2+]i but significantly decreased forward scatter and increased annexin-V-binding. Acrolein further triggered slight, but significant hemolysis and increased ceramide formation in erythrocytes. Acrolein (50 µM induced annexin-V-binding was significantly blunted in the nominal absence of extracellular Ca2+. Acrolein augmented the annexin-V-binding following treatment with Ca2+ ionophore ionomycin (1 µM. Conclusion: Acrolein stimulates suicidal erythrocyte death or eryptosis, an effect at least in part due to stimulation of ceramide formation with subsequent sensitisation of the erythrocytes to cytosolic Ca2+.

  1. Measurement of pO2 in a Pre-clinical Model of Rabbit Tumor Using OxyChip, a Paramagnetic Oxygen Sensor.

    Science.gov (United States)

    Hou, H; Khan, N; Kuppusamy, P

    2017-01-01

    The objective of this work was to establish a novel and robust technology, based on electron paramagnetic resonance (EPR) oximetry, as a practical tool for measurement of tumor oxygen. Previously, we have reported on the development of oxygen-sensing paramagnetic crystals (LiNc-BuO) encapsulated in a biocompatible polymer, called OxyChip. In this report we present our recent data on the use of OxyChip for pO 2 measurements in the tumor of a pre-clinical, large-animal rabbit model. The results establish that OxyChip is capable of noninvasive and repeated measurement of pO 2 in a large animal model.

  2. Erythrocyte survival studies in a rat myelogenous leukemia

    International Nuclear Information System (INIS)

    Derelanko, M.J.; Meagher, R.C.; Lobue, J.; Khouri, J.A.; Gordon, A.S.

    1982-01-01

    To determine the extent intrinsic erythrocyte defects and/or extrinsic factors were involved in anemia of rats bearing Shay chloroleukemia (SCL), survival of 3 H-DFP labeled erythrocytes was studied in leukemic and nonleukemic hosts. Red blood cells labeled before induction of leukemia, were rapidly lost from the peripheral circulation of SCL rats in terminal stages of disease. However, labeled erythrocytes from terminal SCL animals displayed normal lifespans when transfused into nonleukemic controls. Thus the anemia of this leukemia probably resulted from extrinsic factors associated with the leukemic process. Hemorrhage appeared to be primarily responsible for the anemia of this disease

  3. Lipopeptide-Induced Suicidal Erythrocyte Death Correlates with the Degree of Acylation

    Directory of Open Access Journals (Sweden)

    Abdulla Al Mamun Bhuyan

    2017-01-01

    Full Text Available Background/Aims: Consequences of bacterial infection include anemia, which could result from stimulation of suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Bacterial components known to stimulate eryptosis include lipopeptides. Signaling mediating the triggering of eryptosis include increased cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and cellular accumulation of ceramide. The present study aimed to define the molecular requirements for lipopeptide-induced cell membrane scrambling. Methods: Human erythrocytes were incubated for 48 hours in the absence and presence of 1 or 5 µg/ml of the synthetic lipopeptides Pam1 (lipopeptide with one fatty acid, Pam2 (lipopeptide with two fatty acids, or Pam3 (lipopeptide with three fatty acids. In the following phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCF dependent fuorescence, and ceramide abundance utilizing specific antibodies. Results: Pam1 (5 µg/ml, Pam2 (5 µg/ml and Pam3 (1 and 5 µg/ml significantly increased the percentage of annexin-V-binding to erythrocytes in a dose dependent manner, which was largely independent of Ca2+. Pam1-3 increased the percentage of both, swollen and shrunken erythrocytes without significantly modifying the average forward scatter. They also increased reactive oxygen species (ROS and ceramide abundance. In all assays the effect on eryptosis increased with increasing number of fatty acids, with Pam3 showing always the strongest effect. In contrast, a comparison of the effect of Pam1-3 on TLR2 dependent immune stimulation showed that not Pam3 but Pam2 displayed the strongest activity, and that immune stimulation was triggered at much lower concentrations than eryptosis. Conclusions: Lipopeptides are not only important

  4. Influence of reductive diet and physical aerobic training on binding and degradation of 125J-insulin by erythrocyte receptors in children with simple obesity

    International Nuclear Information System (INIS)

    Szczesniak, L.; Rychlewski, T.; Kasprzak, Z.; Banaszak, F.

    1994-01-01

    Insuline resistance, expressed by lower insuline binding by receptors, is related to the obesity. Improvement of the binding was observed together with reduction of body weight and in result of physical exercise. In the work was investigated an influence of complex result of reductive diet at the level of 1300-1500 kcal and systematic half-an-hour aerobic exercise on binding and degradation of 125 J-insulin by erythrocyte receptors in children with simple obesity. The rest binding of insulin by erythrocyte receptors in obese children was compared with the result observed in the children having normal body weight. Results of these researches confirm that systematic physical exercise connected with reductive diet improves the indexes of lipid balance, increases efficiency of the organism, estimated by maximal oxygen absorption, decreases body weight and improves binding of 125 J-insulin to erythrocyte receptors. (authors)

  5. Radiation damage to human erythrocytes. Relative contribution of hydroxyl and chloride radicals in N{sub 2}O-saturated buffers

    Energy Technology Data Exchange (ETDEWEB)

    Krokosz, Anita [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, 90 237 Lodz (Poland)], E-mail: krokosz@biol.uni.lodz.pl; Komorowska, Magdalena A.; Szweda-Lewandowska, Zofia [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, 90 237 Lodz (Poland)

    2008-06-15

    The erythrocyte suspensions in Na-phosphate buffered isotonic NaCl solution (PBS) or Na-phosphate isotonic buffer (PB) (hematocrit 1%) were irradiated with the dose of 400 Gy under N{sub 2}O. Erythrocytes were incubated in the medium in which the cells were irradiated or in fresh PBS. The level of damage to cells was estimated on the basis of the course of post-radiation hemolysis and hemoglobin (Hb) oxidation. The medium in which the cells were irradiated and incubated influenced the course of the post-radiation hemolysis and Hb oxidation as well as some other parameters. We discussed the contribution of hydroxyl and chloride radicals in the initiation of erythrocyte damage and oxygen modification of these processes.

  6. Cytometric quantification of singlet oxygen in the human malaria parasite Plasmodium falciparum

    NARCIS (Netherlands)

    Butzloff, Sabine; Groves, Matthew R; Wrenger, Carsten; Müller, Ingrid B

    The malaria parasite Plasmodium falciparum proliferates within human erythrocytes and is thereby exposed to a variety of reactive oxygen species (ROS) such as hydrogen peroxide, hydroxyl radical, superoxide anion, and highly reactive singlet oxygen ((1)O(2)). While most ROS are already well studied

  7. Oxygen toxicity

    Directory of Open Access Journals (Sweden)

    C. A. van der Westhuizen

    1990-07-01

    Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

  8. Bio-field array: a dielectrophoretic electromagnetic toroidal excitation to restore and maintain the golden ratio in human erythrocytes.

    Science.gov (United States)

    Purnell, Marcy C; Butawan, Matthew B A; Ramsey, Risa D

    2018-06-01

    Erythrocytes must maintain a biconcave discoid shape in order to efficiently deliver oxygen (O 2 ) molecules and to recycle carbon dioxide (CO 2 ) molecules. The erythrocyte is a small toroidal dielectrophoretic (DEP) electromagnetic field (EMF) driven cell that maintains its zeta potential (ζ) with a dielectric constant (ԑ) between a negatively charged plasma membrane surface and the positively charged adjacent Stern layer. Here, we propose that zeta potential is also driven by both ferroelectric influences (chloride ion) and ferromagnetic influences (serum iron driven). The Golden Ratio, a function of Phi φ, offers a geometrical mathematical measure within the distinct and desired curvature of the red blood cell that is governed by this zeta potential and is required for the efficient recycling of CO 2 in our bodies. The Bio-Field Array (BFA) shows potential to both drive/fuel the zeta potential and restore the Golden Ratio in human erythrocytes thereby leading to more efficient recycling of CO 2 . Live Blood Analyses and serum CO 2 levels from twenty human subjects that participated in immersion therapy sessions with the BFA for 2 weeks (six sessions) were analyzed. Live Blood Analyses (LBA) and serum blood analyses performed before and after the BFA immersion therapy sessions in the BFA pilot study participants showed reversal of erythrocyte rheological alterations (per RBC metric; P = 0.00000075), a morphological return to the Golden Ratio and a significant decrease in serum CO 2 (P = 0.017) in these participants. Immersion therapy sessions with the BFA show potential to modulate zeta potential, restore this newly defined Golden Ratio and reduce rheological alterations in human erythrocytes. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  9. Decreased level of 2,3-diphosphoglycerate and alteration of structural integrity in erythrocytes infected with Plasmodium falciparum in vitro.

    Science.gov (United States)

    Dubey, M L; Hegde, Ramakrishna; Ganguly, N K; Mahajan, R C

    2003-04-01

    2,3-Diphosphoglycerate (2,3-DPG), an intracellular metabolite of glycolytic pathway is known to affect the oxygen binding capacity of haemoglobin and mechanical properties of the red blood cells. 2,3-DPG levels have been reported to be elevated during anaemic conditions including visceral leishmaniasis. 2,3-DPG activity in P. falciparum infected red blood cells, particularly in cells infected with different stages of the parasite and its relationship with structural integrity of the cells is not known. Chloroquine sensitive and resistant strains of P. falciparum were cultured in vitro and synchronized cultures of ring, trophozoite and schizont stage rich cells along with the uninfected control erythrocytes were assayed for 2,3-DPG activity and osmotic fragility. It was observed that in both the strains, in infected erythrocytes the 2,3-DPG activity gradually decreased and osmotic fragility gradually increased as the parasite matured from ring to schizont stage. The decrease in 2,3-DPG may probably be due to increased pyruvate kinase activity of parasite origin, which has been shown in erythrocytes infected with several species of Plasmodium. The absence of compensatory increase in 2,3-DPG in P. falciparum infected erythrocytes may aggravate hypoxia due to anaemia in malaria and probably may contribute to hypoxia in cerebral malaria. As 2,3-DPG was not found to be increased in erythrocytes parasitized with P. falciparum, the increased osmotic fragility observed in these cells is not due to increased 2,3-DPG as has been suggested in visceral leishmaniasis.

  10. Determination of dissolved oxygen in saline waters applying mathematical methods and as a membrane electrode sensor; Determinacion de oxigeno disuelto en aguas salinas aplicando modelos matematicos y como sensor electrodo de membrana

    Energy Technology Data Exchange (ETDEWEB)

    Mayari, R.; Espinosa, M. C.; Ruiz, M. [Centro Nacional de Investigaciones Ceintificas. La Habana (Cuba); Romero, E. [Universidad de Huelva (Spain)

    2000-07-01

    This work shows as specific methodology for the determination of dissolved oxygen in saline waters that allows to consider the variations of temperature and of concentration of salts. Both factors influence the solubility of the gases in water, making possible in place measurements, in bodies of water with content of salts unto of the concentration of sea water, with greater dependability. The mathematical models obtained are shown, the errors due to equipment, as well as the results obtained when applying this methodology in saline waters with diverse levels of contamination this allows to discern when the decrease of dissolved oxygen levels is due to an increase in the salinity or to an increase in the contamination of the water body. (Author) 7 refs.

  11. Erythrocyte Sedimentation Rate (ESR): MedlinePlus Lab Test Information

    Science.gov (United States)

    ... K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2 nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Erythrocyte Sedimentation Rate (ESR); p. 267– ...

  12. Erythrocytes for Drug Delivery and their Applications: A Review ...

    African Journals Online (AJOL)

    , dogs, rabbits, rats and mice. Encapsulation in erythrocytes drastically changes the pharmacokinetic properties of drugs in both animals and humans, enhancing liver and spleen uptake and targeting the reticulo-endothelial system (RES).

  13. Spin labelling of human erythrocytes with nitroxide radicals

    International Nuclear Information System (INIS)

    Chagalj, C.; DePaoli, T.C.P.; Hager, A.A.; Palaoro, L.A.; Rubin de Celis, E.; Farach, H.A.; Poole, C.P. jr

    1984-01-01

    Human erythrocytes were labelled with nitroxide, the spin label SYNVAR 101, under various experimantal conditions. A study was made of the influence of antireductants on the labelling efficiency and the kinetics of the radical decay during the labelling process

  14. Insulin binding to erythrocytes after acute 16-methyleneprednisolone ingestion.

    Science.gov (United States)

    Dwenger, A; Holle, W; Zick, R; Trautschold, I

    1982-10-01

    The binding of [125I]insulin to erythrocytes, glucose and insulin were determined before and 1, 7 and 35 days after ingestion of 2 X 60-methyleneprednisolone. None of two groups of volunteers (7 males, 4 females showed clear alterations of the insulin binding parameters (Ka and R0), or of the fasting cortisol, glucose and insulin concentrations. These results exclude the possibility that the diabetogenic effect of glucocorticoides is accompanied by an alteration of the insulin receptor characteristics of erythrocytes.

  15. Effects of dietary fat on lipid composition of serum and erythrocytes of the swine and in vitro incorporation of fatty acids into erythrocyte membranes

    International Nuclear Information System (INIS)

    Sato, Hiroaki

    1974-01-01

    Changes in ftty acid patterns of lipids in serum and erythrocytes induced by dietary fats and in vitro incorporation of fatty acids into erythrocyte membranes were investigated with pigs. On feeding various diets, it was found that fatty acid composition of serum and erythrocytes could be modified and altered toward the fatty acid pattern of the diet. In vitro, the incorporation of labelled fatty acids into erythrocyte membranes was accelerated by the addition of cofactors such as lysolecithin, CoA and ATP. Dietary fats also had certain effects on the incorporation of fatty acids into erythrocyte membranes. Erythrocytes, collected from the blood of pigs fed corn oil, incorporated and also released more labelled linoleate than those of pigs fed hydrogenated soybean oil. Palmitic acid was more slowly incorporated into erythrocyte membranes than linoleic acid in the pigs fed both a commercial chow and scheduled meals, indicating selective esterification of fatty acids in the erythrocyte membranes. (author)

  16. Effect of low-oxygen-concentration layer on iron gettering capability of carbon-cluster ion-implanted Si wafer for CMOS image sensors

    Science.gov (United States)

    Onaka-Masada, Ayumi; Nakai, Toshiro; Okuyama, Ryosuke; Okuda, Hidehiko; Kadono, Takeshi; Hirose, Ryo; Koga, Yoshihiro; Kurita, Kazunari; Sueoka, Koji

    2018-02-01

    The effect of oxygen (O) concentration on the Fe gettering capability in a carbon-cluster (C3H5) ion-implanted region was investigated by comparing a Czochralski (CZ)-grown silicon substrate and an epitaxial growth layer. A high Fe gettering efficiency in a carbon-cluster ion-implanted epitaxial growth layer, which has a low oxygen region, was observed by deep-level transient spectroscopy (DLTS) and secondary ion mass spectroscopy (SIMS). It was demonstrated that the amount of gettered Fe in the epitaxial growth layer is approximately two times higher than that in the CZ-grown silicon substrate. Furthermore, by measuring the cathodeluminescence, the number of intrinsic point defects induced by carbon-cluster ion implantation was found to differ between the CZ-grown silicon substrate and the epitaxial growth layer. It is suggested that Fe gettering by carbon-cluster ion implantation comes through point defect clusters, and that O in the carbon-cluster ion-implanted region affects the formation of gettering sinks for Fe.

  17. Platelet inhibition by nitrite is dependent on erythrocytes and deoxygenation.

    Directory of Open Access Journals (Sweden)

    Sirada Srihirun

    Full Text Available Nitrite is a nitric oxide (NO metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated.Platelet aggregation was studied in platelet-rich plasma (PRP and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger, suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes.Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia.

  18. Erythrocyte zinc levels in children with bronchial asthma.

    Science.gov (United States)

    Arik Yilmaz, E; Ozmen, S; Bostanci, I; Misirlioglu, E Dibek; Ertan, U

    2011-12-01

    Zinc deficiency may be suspected to play a role in the pathogenesis, control, and severity of asthma because of its antioxidant, antiapoptotic, and anti-inflammatory effects. We aimed to investigate whether there was any relationship between erythrocyte zinc levels and childhood asthma. The erythrocyte zinc levels of 67 asthmatic and 45 healthy children were analyzed in this case-control study. The mean concentrations of erythrocyte zinc were 1215.8 ± 145.1 µg/dl in asthma patients and 1206.9 ± 119.5 µg/dl in controls with no significant difference (P = 0.472). The erythrocyte zinc level was below 1,000 µg/dl in 6 asthmatic patients (8.9%) and 2 control group patients (4.4%). There was no relationship between erythrocyte zinc levels and duration of follow-up, severity, and control of the asthma (P > 0.05). On the other hand, patients hospitalized for an asthma attack had significantly lower erythrocyte zinc levels compared with nonhospitalized patients and the control group (P = 0.000 and P = 0.004 respectively). This study's findings indicate that asthmatic children are not a risk group for zinc deficiency. We emphasize that checking zinc levels in children who are hospitalized for an asthma attack may be useful. Copyright © 2011 Wiley Periodicals, Inc.

  19. Temperature-dependent binding of cyclosporine to an erythrocyte protein

    International Nuclear Information System (INIS)

    Agarwal, R.P.; Threatte, G.A.; McPherson, R.A.

    1987-01-01

    In this competitive binding assay to measure endogenous binding capacity for cyclosporine (CsA) in erythrocyte lysates, a fixed amount of [ 3 H]CsA plus various concentrations of unlabeled CsA is incubated with aliquots of a test hemolysate. Free CsA is then adsorbed onto charcoal and removed by centrifugation; CsA complexed with a cyclosporine-binding protein (CsBP) remains in the supernate. We confirmed the validity of this charcoal-separation mode of binding analysis by comparison with equilibrium dialysis. Scatchard plot analysis of the results at 4 degrees C yielded a straight line with slope corresponding to a binding constant of 1.9 X 10(7) L/mol and a saturation capacity of approximately 4 mumol per liter of packed erythrocytes. Similar analysis of binding data at 24 degrees C and 37 degrees C showed that the binding constant decreased with increasing temperature, but the saturation capacity did not change. CsBP was not membrane bound but appeared to be freely distributed within erythrocytes. 125 I-labeled CsA did not complex with the erythrocyte CsBP. Several antibiotics and other drugs did not inhibit binding between CsA and CsBP. These findings may explain the temperature-dependent uptake of CsA by erythrocytes in whole blood and suggest that measurement of CsBP in erythrocytes or lymphocytes may help predict therapeutic response or toxicity after administration of CsA

  20. Stimulation of Suicidal Erythrocyte Death by the Antimalarial Drug Mefloquine

    Directory of Open Access Journals (Sweden)

    Rosi Bissinger

    2015-07-01

    Full Text Available Background: The antimalarial drug mefloquine has previously been shown to stimulate apoptosis of nucleated cells. Similar to apoptosis, erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include oxidative stress, increase of cytosolic Ca2+-activity ([Ca2+]i, and ceramide. Methods: Phosphatidylserine abundance at the cell surface was estimated from annexin V binding, cell volume from forward scatter, reactive oxidant species (ROS from 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA fluorescence, [Ca2+]i from Fluo3-fluorescence, and ceramide abundance from specific antibody binding. Results: A 48 h treatment of human erythrocytes with mefloquine significantly increased the percentage of annexin-V-binding cells (≥5 µg/ml, significantly decreased forward scatter (≥5 µg/ml, significantly increased ROS abundance (5 µg/ml, significantly increased [Ca2+]i (7.5 µg/ml and significantly increased ceramide abundance (10 µg/ml. The up-regulation of annexin-V-binding following mefloquine treatment was significantly blunted but not abolished by removal of extracellular Ca2+. Even in the absence of extracellular Ca2+, mefloquine significantly increased annexin-V-binding. Conclusions: Mefloquine treatment leads to erythrocyte shrinkage and erythrocyte membrane scrambling, effects at least partially due to induction of oxidative stress, increase of [Ca2+]i and up-regulation of ceramide abundance.

  1. Diabetic Erythrocytes Test by Correlation Coefficient

    Science.gov (United States)

    Korol, A.M; Foresto, P; Darrigo, M; Rosso, O.A

    2008-01-01

    Even when a healthy individual is studied, his/her erythrocytes in capillaries continually change their shape in a synchronized erratic fashion. In this work, the problem of characterizing the cell behavior is studied from the perspective of bounded correlated random walk, based on the assumption that diffractometric data involves both deterministic and stochastic components. The photometric readings are obtained by ektacytometry over several millions of shear elongated cells, using a home-made device called Erythrodeformeter. We have only a scalar signal and no governing equations; therefore the complete behavior has to be reconstructed in an artificial phase space. To analyze dynamics we used the technique of time delay coordinates suggested by Takens, May algorithm, and Fourier transform. The results suggest that on random-walk approach the samples from healthy controls exhibit significant differences from those from diabetic patients and these could allow us to claim that we have linked mathematical nonlinear tools with clinical aspects of diabetic erythrocytes’ rheological properties. PMID:19415139

  2. Kinetics of heat-damaged homologous erythrocytes

    International Nuclear Information System (INIS)

    Dimitriou, P.A.; Depascouale, A.K.; Germenis, A.E.; Antipas, S.E.P.

    1990-01-01

    A new theoretical five-compartmental model (5CM) was developed for analysis of the clearance of heat-damaged erythroctes (HDE) labelled with chronium 51. Besides the HDE-spleen interaction, this new model also takes into account the interaction between extrasplenic reticuloendothelial (RES) sites and HDE, i.e. the hepatic clearance of fragment erythrocytes (FE). Accordingly, HDE clearance curves are analysed into three exponential components, the fastest of which describes the RES-FE interaction, whereas the others describe the splenic clearance of spherocytes. Therefore, an estimation of the effective liver blood flow for HDE (ELBF) was achieved, along with a series of parameters describing splenic function. The 5CM proved to be more efficient than a previously proposed three-compartmental model (3CM) in the mathematical description of HDE clearance. Comparison was made by applying both models to 37 experimental curves obtained from 20 patients with congenital hemolytic anemias. The values for the splenic function parameters calculated by 5CM analysis and the strong correlations observed among them offer evidence that this model provides an adequate approximation to the real conditions under which HDE clearance takes place. Furthermore, a detailed quantitative analysis of the pooling of spherocytes within the spleen was attempted in this work, and this phenomenon was found to compete with splenic irreversible spherocyte trapping. The ELBF proved to be closely correlated with the hemodynamic splenic parameters, following first-order kinetics, as do low-dose colloids. (orig.)

  3. Oxygen Therapy

    Science.gov (United States)

    ... their breathing to dangerously low levels. Will I need oxygen when I sleep? Usually if you use supplemental oxygen during the ... your health care provider tells you you only need to use oxygen for exercise or sleep. Even if you feel “fine” off of your ...

  4. Morphological characteristics of urine erythrocytes in children with erythrocyturia

    Directory of Open Access Journals (Sweden)

    V.A. Minakova

    2017-09-01

    Full Text Available Background. Nephropathies with erythrocyturia make up about 1/3 of all diseases of the kidneys and the urinary system, and they have some difficulties in differential diagnostics. Quite often, erythrocyturia is the only symptom of these diseases. In connection with this, determination of its origin is an important task in forming the correct diagnosis. Erythrocyturia in most diseases of the lower urinary tract is not accompanied by proteinuria or the presence of cylinders in the urine. The presence of proteinuria (more than 0.3 g/l or 1 g protein in urine per day, along with the appearance of erythrocytic cylinder in the urine sediment, raises suspicion in favor of glomerular or tubular diseases. Glomerular erythrocytes may be detected by means of urea concentration factor (UCF in the urinary sediment as a preliminary test for the determination of the erythrocyturia site. Erythrocytes that pass through the glomerular membrane have a changed form (dysmorphic. Determination of acanthocytes in the urine (ring-shaped erythrocytes with one or several bulges in the form of bubbles of different sizes and types is a more precise criterion of glomerular nephropathy than the presence of dysmorphic erythrocytes. The purpose of the study was to determine the morphological characteristics of urine erythrocytes in children with erythrocyturia, to improve the quality of differential diagnosis. Materials and methods. Determination of the morphological characteristics of urinary erythrocytes using UCF in 73 patients aged 1 to 18 years, of which 45 (61.6 % are patients with hematuric form of glomerulonephritis, 23 (31.5 % — with hereditary nephritis, and 5 (6.8 % — with dysmetabolic nephropathy. Detection of 50 to 80 % of dysmorphic erythrocytes in the urine sediment and finding in urine of more than 5 % of acanthocytes is a highly sensitive and specific diagnostic criterion for glomerular hematuria. Results. In children with a clinical diagnosis

  5. Organic Electroluminescent Sensor for Pressure Measurement

    Directory of Open Access Journals (Sweden)

    Tomohide Niimi

    2012-10-01

    Full Text Available We have proposed a novel concept of a pressure sensor called electroluminescent pressure sensor (ELPS based on oxygen quenching of electroluminescence. The sensor was fabricated as an organic light-emitting device (OLED with phosphorescent dyes whose phosphorescence can be quenched by oxygenmolecules, and with a polymer electrode which permeates oxygen molecules. The sensor was a single-layer OLED with Platinum (II octaethylporphine (PtOEP doped into poly(vinylcarbazole (PVK as an oxygen sensitive emissive layer and poly(3,4-ethylenedioxythiophene mixed with poly(styrenesulfonate (PEDOT:PSS as an oxygen permeating polymer anode. The pressure sensitivity of the fabricated ELPS sample was equivalent to that of the sensor excited by an illumination light source. Moreover, the pressure sensitivity of the sensor is equivalent to that of conventional pressure-sensitive paint (PSP, which is an optical pressure sensor based on photoluminescence.

  6. Stimulation of Suicidal Erythrocyte Death by Increased Extracellular Phosphate Concentrations

    Directory of Open Access Journals (Sweden)

    Jakob Voelkl

    2014-02-01

    Full Text Available Background/Aim: Anemia in renal insufficiency results in part from impaired erythrocyte formation due to erythropoietin and iron deficiency. Beyond that, renal insufficiency enhances eryptosis, the suicidal erythrocyte death characterized by phosphatidylserine-exposure at the erythrocyte surface. Eryptosis may be stimulated by increase of cytosolic Ca2+-activity ([Ca2+]i. Several uremic toxins have previously been shown to stimulate eryptosis. Renal insufficiency is further paralleled by increase of plasma phosphate concentration. The present study thus explored the effect of phosphate on erythrocyte death. Methods: Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, and [Ca2+]i from Fluo3-fluorescence. Results: Following a 48 hours incubation, the percentage of phosphatidylserine exposing erythrocytes markedly increased as a function of extracellular phosphate concentration (from 0-5 mM. The exposure to 2 mM or 5 mM phosphate was followed by slight but significant hemolysis. [Ca2+]i did not change significantly up to 2 mM phosphate but significantly decreased at 5 mM phosphate. The effect of 2 mM phosphate on phosphatidylserine exposure was significantly augmented by increase of extracellular Ca2+ to 1.7 mM, and significantly blunted by nominal absence of extracellular Ca2+, by additional presence of pyrophosphate as well as by presence of p38 inhibitor SB203580. Conclusion: Increasing phosphate concentration stimulates erythrocyte membrane scrambling, an effect depending on extracellular but not intracellular Ca2+ concentration. It is hypothesized that suicidal erythrocyte death is triggered by complexed CaHPO4.

  7. Insulin radioreceptor assay on murine splenic leukocytes and peripheral erythrocytes

    International Nuclear Information System (INIS)

    Shimizu, F.; Kahn, R.

    1982-01-01

    Insulin radioreceptor assays were developed using splenic leukocytes and peripheral erythrocytes from individual mice. Splenic leukocytes were prepared using an NH 4 Cl buffer which did not alter insulin binding, but gave much higher yields than density gradient methods. Mouse erythrocytes were isolated from heparinized blood by three passages over a Boyum gradient, and a similar buffer was used to separate cells from free [ 125 I]iodoinsulin at the end of the binding incubation. Insulin binding to both splenic leukocytes and peripheral erythrocytes had typical pH, temperature, and time dependencies, and increased linearly with an increased number of cells. Optimal conditions for the splenic leukocytes (6 x 10 7 /ml) consisted of incubation with [ 125 I]iodoinsulin at 15 C for 2 h in Hepes buffer, pH 8.0. In cells from 20 individual mice, the specific [ 125 I]iodoinsulin binding was 2.6 +/- 0.1% (SEM), and nonspecific binding was 0.3 +/- 0.04% (10.6% of total binding). Erythrocytes (2.8 x 10 9 /ml) were incubated with [ 125 ]iodoinsulin at 15 C for 2 h in Hepes buffer, pH 8.2. In cells from 25 individual mice, the specific [ 125 I]iodoinsulin binding was 4.5 +/- 0.2%, and nonspecific binding was 0.7 +/- 0.03% (13.6% of total binding). In both splenic leukocytes and peripheral erythrocytes, analysis of equilibrium binding data produced curvilinear Scatchard plots with approximately 3500 binding sites/leukocyte and 20 binding sites/erythrocyte. These data demonstrate that adequate numbers of splenic leukocytes and peripheral erythrocytes can be obtained from individual mice to study insulin binding in a precise and reproducible manner

  8. Oxygen Therapy

    Directory of Open Access Journals (Sweden)

    Bonnie Solmes

    2000-01-01

    Full Text Available LTOT is prescribed for people with chronic lung disease in whom there is a decrease in the ability of the lungs to supply enough oxygen to the body. The heart is obliged to pump faster to meet the body's oxygen requirements. This may place undue stress on the heart, resulting in palpitations, dizziness and fatigue. A low oxygen level in arterial blood is also harmful to the heart, the brain and the pulmonary blood vessels. Oxygen therapy is used to break this cycle. A person with low blood oxygen will often be able to accomplish more with less fatigue with the help of supplemental oxygen therapy. Shortness of breath is a mechanical problem resulting from the effects of chronic obstructive pulmonary disease. Oxygen therapy may or may not reduce shortness of breath, but it will help the lungs and heart to function with less stress.

  9. Erythrocytes antioxygant parameters in works occupationally to law levels of ionizing radiation

    International Nuclear Information System (INIS)

    Klucinski, P.; Martirosian, G.; Wojcik, A.; Grabowska-Bochenek, R.; Gminmski, J.; Mazur, B.; Hrycek, A.; Cieslik, P.

    2008-01-01

    It has been postulated that ionizing radiation generates reactive oxygen species (ROS). ROS are annihilated by an intracellular enzymatic system composed mainly of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Workers of X-ray departments are occupationally exposed to long-term low levels of ionizing radiation, which may affect their antioxidant status. Erythrocyte activities of SOD, CAT and GPx were measured in 45 workers of X-ray departments and 30 persons who constituted the control group. Subgroups with respect to sex and cigarette smoking were selected. Colorimetric method was used for determination erythrocyte activities of SOD, CAT and GPx. A significant decrease of GPx, SOD and CAT activity in workers as compared to controls was observed. Lower activity of SOD and GPx in female and GPx in male subgroup was found. SOD was significantly more elevated in smoking workers than in the non-smoking staff. Moreover non-smoking employees showed lower SOD and GPx activity in comparison to the non-smoking control. GPx decrease was found in smoking workers in comparison to the smoking control. Additionally, smoking workers showed lower activity of GPx and CAT compared to non-smoking control. (author)

  10. Dietary nucleotide supplementation raises erythrocyte 2, 3-diphosphoglycerate concentration in neonatal rats.

    Science.gov (United States)

    Scopesi, F; Verkeste, C M; Paola, D; Gazzolo, D; Pronzato, M A; Bruschettini, P L; Marinari, U M

    1999-03-01

    The present study was designed to test if dietary intake of nucleotides increases erythrocyte 2,3-diphosphoglycerate (2,3-DPG) in neonatal rats. To this end, rat pups were fed a nucleotide-supplemented formula (S, n = 14) from d 9 until d 16 after birth. The results were compared with those obtained from a group of breast-fed pups (C, n = 14) and a group of pups artificially fed with nucleotide-free formula (NS, n = 14). Neonatal weight, 2,3-DPG concentration, hematocrit (Hct) and hemoglobin concentration (Hb) were determined before the experiment (d 9) and after 7 d of treatment (d 16). In all groups, 2,3-DPG concentration was greater at d 16 than d 9, and the increase was greater in the S group than in the NS group. Alterations in neonatal weight, Hct and Hb concentration did not differ among the groups. On d 16 the 2, 3-DPG/Hb ratio, reflecting the affinity of hemoglobin for oxygen, was significantly higher in the C and S groups than in the NS group. We conclude that in neonatal rats, dietary nucleotides increase erythrocyte 2,3-DPG concentration. Studies need to be conducted in humans to assess the effect of this increase on both neonatal peripheral hemodynamics and metabolism in this species.

  11. Estimation of vascular spaces using radiolabeled erythrocytes

    International Nuclear Information System (INIS)

    Nasseri, K.

    2002-01-01

    Measurement of vascular volume is important in many physiological and pathological studies. For isolated organ preparations, this is usually performed using normal erythrocytes (red blood cell; RBC) and in the whole body studies, labeled RBCs are used. The aim of the present project was to compare the two methods in model organ (the liver) in terms of sensitivity and packed RBCs are suspended in normal saline. 100 u l aliquot is injected into the portal vein of rat. The outflow samples collected, hemo lysed and measured by colorimeter. In the second method, the packed RBCs are incubated with Cr-sodium and then resuspended in normal saline. A bolus of labelled RBCs with known activity is injected into portal vein of rats and the outflow activity is determined by gamma spectrometry. The extend of Cr binding to RBCs was investigated; in all experiments less than 2% of the total radioactivity after washing was extra cellular. Both methods were tested in 30 preparations. The normalized frequency outflow profiles of RBCs counted by two methods were then compared. The standard curves of the two methods were also obtained and the correlation was compared. The shape of the curves and calculated vascular volume obtained from the two methods were similar. A good correlation was observed between the methods of measurement of RBCs. The results indicated the second method is more precise and sensitive to low grade changes while the first method is quicker and better preserves RBCs than the second method. Theses advantages, together with safety considerations, favour the first method when it is applicable

  12. Sensor for ionizable elements

    International Nuclear Information System (INIS)

    Berkey, E.; Reed, W.A. III; Hickam, W.M.

    1977-01-01

    Sensor to detect thermally ionizable elements or molucules in air, water vapour or oxygen or to be used as alkali leak detector in vacuum systems, e.g. in the pipe system of a liquid-metal cooled FBR. The sensor consists of an filament made of thorium-containing iridium as cathode with a temperature upto 1000 0 C and an anode sheet of molybdenum, nickel or stainless steal. (ORU) [de

  13. Water quality sensor

    International Nuclear Information System (INIS)

    Ishizuka, Keiko; Takahashi, Masanori; Watanabe, Atsushi; Ibe, Hidefumi.

    1994-01-01

    The sensor of the present invention can directly measure oxygen/hydrogen peroxide concentrations in reactor water under radiation irradiation condition, and it has a long life time. Namely, an oxygen sensor comprises electrodes attached on both sides of high temperature/radiation resistant ion conductive material in which ions are sufficiently diffused within a temperature range of from a room temperature to 300degC. It has a performance for measuring electromotive force caused by the difference of a partial pressure between a reference gas and a gas to be measured contained in the high temperature/radiation resistant material. A hydrogen peroxide sensor has the oxygen sensor described above, to which a filter for causing decomposition of hydrogen peroxide is attached. The sensor of the present invention can directly measure oxygen/hydrogen peroxide concentrations in a reactor water of a BWR type reactor under high temperature/radiation irradiation condition. Accordingly, accurate water quality environment in the reactor water can be recognized. As a result, determination of incore corrosion environment is established thereby enabling to attain reactor integrity, safety and long life. (I.S.)

  14. A reduced-order adaptive neuro-fuzzy inference system model as a software sensor for rapid estimation of five-day biochemical oxygen demand

    Science.gov (United States)

    Noori, Roohollah; Safavi, Salman; Nateghi Shahrokni, Seyyed Afshin

    2013-07-01

    The five-day biochemical oxygen demand (BOD5) is one of the key parameters in water quality management. In this study, a novel approach, i.e., reduced-order adaptive neuro-fuzzy inference system (ROANFIS) model was developed for rapid estimation of BOD5. In addition, an uncertainty analysis of adaptive neuro-fuzzy inference system (ANFIS) and ROANFIS models was carried out based on Monte-Carlo simulation. Accuracy analysis of ANFIS and ROANFIS models based on both developed discrepancy ratio and threshold statistics revealed that the selected ROANFIS model was superior. Pearson correlation coefficient (R) and root mean square error for the best fitted ROANFIS model were 0.96 and 7.12, respectively. Furthermore, uncertainty analysis of the developed models indicated that the selected ROANFIS had less uncertainty than the ANFIS model and accurately forecasted BOD5 in the Sefidrood River Basin. Besides, the uncertainty analysis also showed that bracketed predictions by 95% confidence bound and d-factor in the testing steps for the selected ROANFIS model were 94% and 0.83, respectively.

  15. Detection of Occult Erythrocytic Membrane Damages upon Pharmacological Exposures

    Directory of Open Access Journals (Sweden)

    P. Yu. Alekseyeva

    2007-01-01

    Full Text Available Blood administration of pharmaceuticals may cause occult effects of these agents on erythrocytic membranes. These effects may damage and cause additional membrane defects, but may strengthen. The type and degree of the effects of an agent were detected by calibrated irreversible electroporation with a pulsed electric field (PEF. The paper considers the erythrocytic membranous effects of a wide concentration range of agents used in anesthesiology, such as esmerone, tracrium, and mar-caine-adrenaline. Under the action of PEF and esmerone at the normal concentration N, the rate of erythrocytic hemolysis increased by several times as compared with the control. The similar effect also occurred when esmerone was added at the concentration C=10N. Tracrium exerted a fixing effect on erythrocytic membranes. Upon a combined exposure to PEF and tracrium in the normal concentration C=N; erythrocytic hemolysis was slow. So was with the concentration C=10N. The rate of hemolysis of the red blood cells subjected to a combined action of marcaine adrenaline at the normal concentration C=N and even at the concentration C=10N and PEF was comparable with the hemolytic rate of the reference suspension. 

  16. MODIFICATION OF ERYTHROCYTE MEMBRANE PROTEINS WITH POLYETHYLENE GLYCOL 1500

    Directory of Open Access Journals (Sweden)

    N. G. Zemlianskykh

    2016-10-01

    Full Text Available The aim of the work was to study the effect of polyethylene glycol PEG-1500 on the Ca2+-ATPase activity and changes in CD44 surface marker expression in human erythrocyte membranes. Determination of the Ca2+-ATPase activity was carried out in sealed erythrocyte ghosts by the level of accumulation of inorganic phosphorus. Changes in the expression of CD44 and amount of CD44+-erythrocytes were evaluated by flow cytometry. The inhibition of Ca2+-ATPase activity and a reduction in the level of CD44 expression and also the decrease in the amount CD44+-cells were found, reflecting a fairly complex restructuring in the membrane-cytoskeleton complex of erythrocytes under the influence of PEG-1500. Effect of PEG-1500 on the surface CD44 marker could be mediated by modification of proteins of membrane-cytoskeleton complex, as indicated by accelerated loss of CD44 in erythrocyte membranes after application of protein cross-linking reagent diamide. Reduced activity of Ca2+-ATPase activity may contribute to the increase in intracellular Ca2+ level and thus leads to a modification of interactions of integral proteins with cytoskeletal components that eventually could result in membrane vesiculation and decreasing in expression of the CD44 marker, which is dynamically linked to the cytoskeleton.

  17. Erythrocyte and platelet fatty acids in retinitis pigmentosa.

    Science.gov (United States)

    Stanzial, A M; Bonomi, L; Cobbe, C; Olivieri, O; Girelli, D; Trevisan, M T; Bassi, A; Ferrari, S; Corrocher, R

    1991-05-01

    The fatty acid composition and the glutathione-peroxidase activity (GSH-Px) of erythrocytes and platelets, the production of malondialdehyde (MDA) by platelets and the activity of the main systems of transmembrane cation transport in erythrocyte have been studied in 12 patients (5 males and 7 females) affected by retinitis pigmentosa (RP). A remarkable increase of saturated fatty acids (SFA), particularly of stearic acid (C18:0), has been noted in these patients. The reduced unsaturated/saturated fatty acids ratio (PUFA/SFA) observed in both erythrocytes and platelets and the decrease of arachidonic acid in platelets may depend by an active peroxidation process as documented by the increase of MDA. Platelet glutathione-peroxidase (PTL-GSH-PX) and plasma retinol were in the normal range, whereas erythrocyte glutathione-peroxidase (E-GSH-PX), MDA and plasma alfa-toco-pherol were increased in patients with RP. The activities of Na(+)-K+ pump, cotransport and Na(+)-Li+ countertransport were normal in RP erythrocytes.

  18. Very Deep Convolutional Neural Networks for Morphologic Classification of Erythrocytes.

    Science.gov (United States)

    Durant, Thomas J S; Olson, Eben M; Schulz, Wade L; Torres, Richard

    2017-12-01

    Morphologic profiling of the erythrocyte population is a widely used and clinically valuable diagnostic modality, but one that relies on a slow manual process associated with significant labor cost and limited reproducibility. Automated profiling of erythrocytes from digital images by capable machine learning approaches would augment the throughput and value of morphologic analysis. To this end, we sought to evaluate the performance of leading implementation strategies for convolutional neural networks (CNNs) when applied to classification of erythrocytes based on morphology. Erythrocytes were manually classified into 1 of 10 classes using a custom-developed Web application. Using recent literature to guide architectural considerations for neural network design, we implemented a "very deep" CNN, consisting of >150 layers, with dense shortcut connections. The final database comprised 3737 labeled cells. Ensemble model predictions on unseen data demonstrated a harmonic mean of recall and precision metrics of 92.70% and 89.39%, respectively. Of the 748 cells in the test set, 23 misclassification errors were made, with a correct classification frequency of 90.60%, represented as a harmonic mean across the 10 morphologic classes. These findings indicate that erythrocyte morphology profiles could be measured with a high degree of accuracy with "very deep" CNNs. Further, these data support future efforts to expand classes and optimize practical performance in a clinical environment as a prelude to full implementation as a clinical tool. © 2017 American Association for Clinical Chemistry.

  19. Atorvastatin acts synergistically with N-acetyl cysteine to provide therapeutic advantage against Fas-activated erythrocyte apoptosis during chronic arsenic exposure in rats

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Debabrata; Sen, Gargi; Sarkar, Avik; Biswas, Tuli

    2011-01-01

    Arsenic is an environmental toxicant that reduces the lifespan of circulating erythrocytes during chronic exposure. Our previous studies had indicated involvement of hypercholesterolemia and reactive oxygen species (ROS) in arsenic-induced apoptotic death of erythrocytes. In this study, we have shown an effective recovery from arsenic-induced death signaling in erythrocytes in response to treatment with atorvastatin (ATV) and N-acetyl cysteine (NAC) in rats. Our results emphasized on the importance of cholesterol in the promotion of ROS-mediated Fas signaling in red cells. Arsenic-induced activation of caspase 3 was associated with phosphatidylserine exposure on the cell surface and microvesiculation of erythrocyte membrane. Administration of NAC in combination with ATV, proved to be more effective than either of the drugs alone towards the rectification of arsenic-mediated disorganization of membrane structural integrity, and this could be linked with decreased ROS accumulation through reduced glutathione (GSH) repletion along with cholesterol depletion. Moreover, activation of caspase 3 was capable of promoting aggregation of band 3 with subsequent binding of autologous IgG and opsonization by C3b that led to phagocytosis of the exposed cells by the macrophages. NAC-ATV treatment successfully amended these events and restored lifespan of erythrocytes from the exposed animals almost to the control level. This work helped us to identify intracellular membrane cholesterol enrichment and GSH depletion as the key regulatory points in arsenic-mediated erythrocyte destruction and suggested a therapeutic strategy against Fas-activated cell death related to enhanced cholesterol and accumulation of ROS.

  20. Identification of Stages of Erythroid Differentiation in Bone Marrow and Erythrocyte Subpopulations in Blood Circulation that Are Preferentially Lost in Autoimmune Hemolytic Anemia in Mouse.

    Directory of Open Access Journals (Sweden)

    Sreoshi Chatterjee

    Full Text Available Repeated weekly injections of rat erythrocytes produced autoimmune hemolytic anemia (AIHA in C57BL/6 mice after 5-6 weeks. Using the double in vivo biotinylation (DIB technique, recently developed in our laboratory, turnover of erythrocyte cohorts of different age groups during AIHA was monitored. Results indicate a significant decline in the proportion of reticulocytes, young and intermediate age groups of erythrocytes, but a significant increase in the proportion of old erythrocytes in blood circulation. Binding of the autoantibody was relatively higher to the young erythrocytes and higher levels of intracellular reactive oxygen species (ROS were also seen in these cells. Erythropoietic activity in the bone marrows and the spleen of AIHA induced mice was examined by monitoring the relative proportion of erythroid cells at various stages of differentiation in these organs. Cells at different stages of differentiation were enumerated flow cytometrically by double staining with anti-Ter119 and anti-transferrin receptor (CD71 monoclonal antibodies. Erythroid cells in bone marrow declined significantly in AIHA induced mice, erythroblast C being most affected (50% decline. Erythroblast C also recorded high intracellular ROS level along with increased levels of membrane-bound autoantibody. No such decline was observed in spleen. A model of AIHA has been proposed indicating that binding of autoantibodies may not be a sufficient condition for destruction of erythroid cells in bone marrow and in blood circulation. Last stage of erythropoietic differentiation in bone marrow and early stages of erythrocytes in blood circulation are specifically susceptible to removal in AIHA.

  1. Determination of somatic mutations in human erythrocytes by cytometry

    International Nuclear Information System (INIS)

    Jensen, R.H.; Langlois, R.G.; Bigbee, W.L.

    1985-01-01

    Flow cytometric assays of human erythrocytes labeled with monoclonal antibodies specific for glycophorin A were used to enumerate variant cells that appear in peripheral blood as a result of somatic gene-loss mutations in erythrocyte precursor cells. The assay was performed on erythrocytes from 10 oncology patients who had received at least one treatment from radiation or mutagenic chemotherapy at least 3 weeks before being assayed. The patients were suffering from many different malignancies (e.g., breast, renal, bone, colon and lung), and were treated with several different mutagenic therapeutics (e.g., cisplatinum, adriamycin, daunomycin, or cyclophosphamide). The frequency of these variant cells is an indication of the amount of mutagenic damage accumulated in the individual's erythropoietic cell population. Comparing these results to HPRT clonogenic assays, we find similar baseline frequencies of somatic mutation as well as similar correlation with mutagenic exposures. 9 refs., 3 figs., 1 tab

  2. Determination of somatic mutations in human erythrocytes by cytometry

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, R.H.; Langlois, R.G.; Bigbee, W.L.

    1985-06-21

    Flow cytometric assays of human erythrocytes labeled with monoclonal antibodies specific for glycophorin A were used to enumerate variant cells that appear in peripheral blood as a result of somatic gene-loss mutations in erythrocyte precursor cells. The assay was performed on erythrocytes from 10 oncology patients who had received at least one treatment from radiation or mutagenic chemotherapy at least 3 weeks before being assayed. The patients were suffering from many different malignancies (e.g., breast, renal, bone, colon and lung), and were treated with several different mutagenic therapeutics (e.g., cisplatinum, adriamycin, daunomycin, or cyclophosphamide). The frequency of these variant cells is an indication of the amount of mutagenic damage accumulated in the individual's erythropoietic cell population. Comparing these results to HPRT clonogenic assays, we find similar baseline frequencies of somatic mutation as well as similar correlation with mutagenic exposures. 9 refs., 3 figs., 1 tab.

  3. Specific binding of beta-endorphin to normal human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Chenet, B.; Hollis, V. Jr.; Kang, Y.; Simpkins, C.

    1986-03-05

    Beta-endorphin (BE) exhibits peripheral functions which may not be mediated by interactions with receptors in the brain. Recent studies have demonstrated binding of BE to both opioid and non-opioid receptors on lymphocytes and monocytes. Abood has reported specific binding of /sup 3/H-dihydromorphine in erythrocytes. Using 5 x 10/sup -11/M /sup 125/I-beta-endorphin and 10/sup -5/M unlabeled BE, they have detected 50% specific binding to human erythrocytes. This finding is supported by results from immunoelectron microscopy using rabbit anti-BE antibody and biotinylated secondary antibody with avidin-biotin complexes horseradish peroxidase. Binding is clearly observed and is confined to only one side of the cells. Conclusions: (1) BE binding to human erythrocytes was demonstrated by radioreceptor assay and immunoelectron microscopy, and (2) BE binding sites exist on only one side of the cells.

  4. Genotoxic Biomarkers in Erythrocytes of Lepidochelys olivacea (Cheloniidae from Colombia

    Directory of Open Access Journals (Sweden)

    Victor Hugo Quiroz Herrera

    2017-09-01

    Full Text Available This research was conducted in the municipality of Bahia Solano, Colombia, and had as a goal to detect damage erythrocytes circulating with nuclear lesions in fifty-five Olive Ridley adult females using acridine orange immunostain, and correlate its frequencies with some physiological and biometric parameters. We determine a micronucleated erythrocytes (MNE frequency of 0.6 ± 0.6 and nuclear buds (NBE of 2.1 ± 1.9. We not found any relationship between the nuclear lesions with physiological or biometric parameters evaluated (Pearson and Kruskal-Wallis, p<0.05. We define a significative statistical difference (p=0.035 between both nuclear lesions frequencies. This results show nuclear damages in erythrocytes of Olive Ridley sea turtle for the first time in Colombia as an outcome of genotoxic stress. Also contributes key information for future research in the ecotoxicology area for endangered marine species.

  5. A novel approach for assessments of erythrocyte sedimentation rate.

    Science.gov (United States)

    Pribush, A; Hatskelzon, L; Meyerstein, N

    2011-06-01

    Previous studies have shown that the dispersed phase of sedimenting blood undergoes dramatic structural changes: Discrete red blood cell (RBC) aggregates formed shortly after a settling tube is filled with blood are combined into a continuous network followed by its collapse via the formation of plasma channels, and finally, the collapsed network is dispersed into individual fragments. Based on this scheme of structural transformation, a novel approach for assessments of erythrocyte sedimentation is suggested. Information about erythrocyte sedimentation is extracted from time records of the blood conductivity measured after a dispersion of RBC network into individual fragments. It was found that the sedimentation velocity of RBC network fragments correlates positively with the intensity of attractive intercellular interactions, whereas no effect of hematocrit (Hct) was observed. Thus, unlike Westergren erythrocyte sedimentation rate, sedimentation data obtained by the proposed method do not require correction for Hct. © 2010 Blackwell Publishing Ltd.

  6. The malaria parasite RhopH protein complex interacts with erythrocyte calmyrin identified from a comprehensive erythrocyte protein library.

    Science.gov (United States)

    Miura, Toyokazu; Takeo, Satoru; Ntege, Edward H; Otsuki, Hitoshi; Sawasaki, Tatsuya; Ishino, Tomoko; Takashima, Eizo; Tsuboi, Takafumi

    2018-06-02

    Malaria merozoite apical organelles; microneme and rhoptry secreted proteins play functional roles during and following invasion of host erythrocytes. Among numerous proteins, the rhoptries discharge high molecular weight proteins known as RhopH complex. Recent reports suggest that the RhopH complex is essential for growth and survival of the malaria parasite within erythrocytes. However, an in-depth understanding of the host-parasite molecular interactions is indispensable. Here we utilized a comprehensive mouse erythrocyte protein library consisting of 443 proteins produced by a wheat germ cell-free system, combined with AlphaScreen technology to identify mouse erythrocyte calmyrin as an interacting molecule of the rodent malaria parasite Plasmodium yoelii RhopH complex (PyRhopH). The PyRhopH interaction was dependent on the calmyrin N-terminus and divalent cation capacity. The finding unveils a recommendable and invaluable usefulness of our comprehensive mouse erythrocyte protein library together with the AlphaScreen technology in investigating a wide-range of host-parasite molecular interactions. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Caffeine inhibits erythrocyte membrane derangement by antioxidant activity and by blocking caspase 3 activation.

    Science.gov (United States)

    Tellone, Ester; Ficarra, Silvana; Russo, Annamaria; Bellocco, Ersilia; Barreca, Davide; Laganà, Giuseppina; Leuzzi, Ugo; Pirolli, Davide; De Rosa, Maria Cristina; Giardina, Bruno; Galtieri, Antonio

    2012-02-01

    The aim of this research was to investigate the effect of caffeine on band 3 (the anion exchanger protein), haemoglobin function, caspase 3 activation and glucose-6-phosphate metabolism during the oxygenation-deoxygenation cycle in human red blood cells. A particular attention has been given to the antioxidant activity by using in vitro antioxidant models. Caffeine crosses the erythrocyte membrane and interacts with the two extreme conformational states of haemoglobin (the T and the R-state within the framework of the simple two states allosteric model) with different binding affinities. By promoting the high affinity state (R-state), the caffeine-haemoglobin interaction does enhance the pentose phosphate pathway. This is of benefit for red blood cells since it leads to an increase of NADPH availability. Moreover, caffeine effect on band 3, mediated by haemoglobin, results in an extreme increase of the anion exchange, particularly in oxygenated erythrocytes. This enhances the transport of the endogenously produced CO(2) thereby avoiding the production of dangerous secondary radicals (carbonate and nitrogen dioxide) which are harmful to the cellular membrane. Furthermore caffeine destabilizes the haeme-protein interactions within the haemoglobin molecule and triggers the production of superoxide and met-haemoglobin. However this damaging effect is almost balanced by the surprising scavenger action of the alkaloid with respect to the hydroxyl radical. These experimental findings are supported by in silico docking and molecular dynamics studies and by what we may call the "caspase silence"; in fact, there is no evidence of any caspase 3 activity enhancement; this is likely due to the promotion of positive metabolic conditions which result in an increase of the cellular reducing power. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  8. Erythrocyte stiffness during morphological remodeling induced by carbon ion radiation.

    Directory of Open Access Journals (Sweden)

    Baoping Zhang

    Full Text Available The adverse effect induced by carbon ion radiation (CIR is still an unavoidable hazard to the treatment object. Thus, evaluation of its adverse effects on the body is a critical problem with respect to radiation therapy. We aimed to investigate the change between the configuration and mechanical properties of erythrocytes induced by radiation and found differences in both the configuration and the mechanical properties with involving in morphological remodeling process. Syrian hamsters were subjected to whole-body irradiation with carbon ion beams (1, 2, 4, and 6 Gy or X-rays (2, 4, 6, and 12 Gy for 3, 14 and 28 days. Erythrocytes in peripheral blood and bone marrow were collected for cytomorphological analysis. The mechanical properties of the erythrocytes were determined using atomic force microscopy, and the expression of the cytoskeletal protein spectrin-α1 was analyzed via western blotting. The results showed that dynamic changes were evident in erythrocytes exposed to different doses of carbon ion beams compared with X-rays and the control (0 Gy. The magnitude of impairment of the cell number and cellular morphology manifested the subtle variation according to the irradiation dose. In particular, the differences in the size, shape and mechanical properties of the erythrocytes were well exhibited. Furthermore, immunoblot data showed that the expression of the cytoskeletal protein spectrin-α1 was changed after irradiation, and there was a common pattern among its substantive characteristics in the irradiated group. Based on these findings, the present study concluded that CIR could induce a change in mechanical properties during morphological remodeling of erythrocytes. According to the unique characteristics of the biomechanical categories, we deduce that changes in cytomorphology and mechanical properties can be measured to evaluate the adverse effects generated by tumor radiotherapy. Additionally, for the first time, the current study

  9. Viral erythrocytic necrosis: Chapter 2.2.7

    Science.gov (United States)

    Winton, James R.; Hershberger, Paul K.

    2014-01-01

    Viral erythrocytic necrosis (VEN), originally termed piscine erythrocytic necrosis, is a condition that has been reported to affect the red blood cells (RBCs) of many species of marine and anadromous fishes in both the Atlantic and Pacific Oceans (Nicholson and Reno 1981; Smail 1982; Wolf 1988; Dannevig and Thorud 1999). Fish with VEN may develop a severe anemia that can reduce their stamina, predispose them to other infections or increase the impact of other stressors (MacMillan et al. 1980; Nicholson and Reno 1981; Meyers et al. 1986; Haney et al. 1992) resulting in population-scale impacts in susceptible species (Hershberger et al. 2009).

  10. The complete amino acid sequence of human erythrocyte diphosphoglycerate mutase.

    Science.gov (United States)

    Haggarty, N W; Dunbar, B; Fothergill, L A

    1983-01-01

    The complete amino acid sequence of human erythrocyte diphosphoglycerate mutase, comprising 239 residues, was determined. The sequence was deduced from the four cyanogen bromide fragments, and from the peptides derived from these fragments after digestion with a number of proteolytic enzymes. Comparison of this sequence with that of the yeast glycolytic enzyme, phosphoglycerate mutase, shows that these enzymes are 47% identical. Most, but not all, of the residues implicated as being important for the activity of the glycolytic mutase are conserved in the erythrocyte diphosphoglycerate mutase. PMID:6313356

  11. Erythrocyte 2,3-diphosphoglycerate depletion associated with hypophosphatemia detected by routine arterial blood gas analysis.

    Science.gov (United States)

    Larsen, V H; Waldau, T; Gravesen, H; Siggaard-Andersen, O

    1996-01-01

    To describe a clinical case where an extremely low erythrocyte 2,3-diphosphoglycerate concentration (2,3-DPG) was discovered by routine blood gas analysis supplemented by computer calculation of derived quantities. The finding of a low 2,3-DPG revealed a severe hypophosphatemia. Open uncontrolled study of a patient case. Intensive care observation during 41 days. A 44 year old woman with an abdominal abscess. Surgical drainage, antibiotics and parenteral nutrition. daily routine blood gas analyses with computer calculation of the hemoglobin oxygen affinity and estimation of the 2,3-DPG. An abrupt decline of 2,3-DPG was observed late in the course coincident with a pronounced hypophosphatemia. The fall in 2,3-DPG was verified by enzymatic analysis. 2,3-DPG may be estimated by computer calculation of routine blood gas data. A low 2,3-DPG which may be associated with hypophosphatemia causes an unfavorable increase in hemoglobin oxygen affinity which reduces the oxygen release to the tissues.

  12. Python erythrocytes are resistant to α-hemolysin from Escherichia coli.

    Science.gov (United States)

    Larsen, Casper K; Skals, Marianne; Wang, Tobias; Cheema, Muhammad U; Leipziger, Jens; Praetorius, Helle A

    2011-12-01

    α-Hemolysin (HlyA) from Escherichia coli lyses mammalian erythrocytes by creating nonselective cation pores in the membrane. Pore insertion triggers ATP release and subsequent P2X receptor and pannexin channel activation. Blockage of either P2X receptors or pannexin channels reduces HlyA-induced hemolysis. We found that erythrocytes from Python regius and Python molurus are remarkably resistant to HlyA-induced hemolysis compared to human and Trachemys scripta erythrocytes. HlyA concentrations that induced maximal hemolysis of human erythrocytes did not affect python erythrocytes, but increasing the HlyA concentration 40-fold did induce hemolysis. Python erythrocytes were more resistant to osmotic stress than human erythrocytes, but osmotic stress tolerance per se did not confer HlyA resistance. Erythrocytes from T. scripta, which showed higher osmotic resistance than python erythrocytes, were as susceptible to HlyA as human erythrocytes. Therefore, we tested whether python erythrocytes lack the purinergic signalling known to amplify HlyA-induced hemolysis in human erythrocytes. P. regius erythrocytes increased intracellular Ca²⁺ concentration and reduced cell volume when exposed to 3 mM ATP, indicating the presence of a P2X₇-like receptor. In addition, scavenging extracellular ATP or blocking P2 receptors or pannexin channels reduced the HlyA-induced hemolysis. We tested whether the low HlyA sensitivity resulted from low affinity of HlyA to the python erythrocyte membrane. We found comparable incorporation of HlyA into human and python erythrocyte membranes. Taken together, the remarkable HlyA resistance of python erythrocytes was not explained by increased osmotic resistance, lack of purinergic hemolysis amplification, or differences in HlyA affinity.

  13. Kinetics of viral load and erythrocytic inclusion body formation in pacific herring artificially infected with erythrocytic necrosis virus

    Science.gov (United States)

    Glenn, Jolene A.; Emmenegger, Eveline J.; Grady, Courtney A.; Roon, Sean R.; Gregg, Jacob L.; Conway, Carla M.; Winton, James R.; Hershberger, Paul K.

    2012-01-01

    Viral erythrocytic necrosis (VEN) is a condition that affects marine and anadromous fish species, including herrings and salmonids, in the Atlantic and Pacific oceans. Infection is frequently associated with severe anemia and causes episodic mortality among wild and hatchery fish when accompanied by additional stressors; VEN can be presumptively diagnosed by (1) light microscopic identification of a single characteristic—a round, magenta-colored, 0.8-μm-diameter inclusion body (IB) within the cytoplasm of erythrocytes and their precursors on Giemsa-stained blood films; or (2) observation (via transmission electron microscopy [TEM]) of the causative iridovirus, erythrocytic necrosis virus (ENV), within erythrocytes or their precursors. To better understand the kinetics of VEN, specific-pathogen-free Pacific herring Clupea pallasii were infected with ENV by intraperitoneal injection. At 1, 4, 7, 10, 14, 21, and 28 d postexposure, samples of blood, spleen, and kidney were collected and assessed (1) via light microscopy for the number of intracytoplasmic IBs in blood smears and (2) via TEM for the number of virions within erythrocytes. The mean prevalence of intracytoplasmic IBs in the blood cells increased from 0% at 0–4 d postexposure to 94% at 28 d postexposure. Viral load within circulating red blood cells peaked at 7 d postexposure, fell slightly, and then reached a plateau. However, blood cells observed within the kidney and spleen tissues demonstrated high levels of ENV between 14 and 28 d postexposure. The results indicate that the viral load within erythrocytes does not correlate well with IB prevalence and that the virus can persist in infected fish for more than 28 d.

  14. Inhibition of lipid oxidation in foods and feeds and hydroxyl radical-treated fish erythrocytes: A comparative study of Ginkgo biloba leaves extracts and synthetic antioxidants

    Directory of Open Access Journals (Sweden)

    Huatao Li

    2016-09-01

    Full Text Available This study explored the effects of butylated hydroxytoluene (BHT and ethoxyquin (EQ and ethyl ether extracts, ethyl acetate extracts (EAE, acetone extracts, ethanol extracts and aqueous extracts of Ginkgo biloba leaves (EGbs on lipid oxidation in a linoleic acid emulsion, fish flesh and fish feed and in hydroxyl radical (·OH-treated carp erythrocytes. The linoleic acid, fish flesh and fish feed were incubated with BHT, EQ and EGbs at 45°C for 8 d, respectively, except for the control group. The lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed was then measured by the ferric thiocyanate method or thiobarbituric acid method. The carp erythrocytes were treated with BHT, EQ or EGbs in the presence of 40 μmol/L FeSO4 and 20 μmol/L H2O2 at 37°C for 6 h, except for the control group. Oxidative stress and apoptosis parameters in carp erythrocytes were then evaluated by the commercial kit. The results showed that BHT, EQ and EGbs inhibited lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed and ·OH-induced phosphatidylserine exposure and DNA fragmentation (the biomarkers of apoptosis in carp erythrocytes. Furthermore, BHT, EQ and EGbs decreased the generation of reactive oxygen species (ROS, inhibited the oxidation of cellular components and restored the activities of enzymatic antioxidants in ·OH-treated carp erythrocytes. Of all examined EGbs, EAE showed the strongest effects. The effects of EAE on lipid oxidation in the linoleic acid emulsion and on superoxide anion and malonaldehyde levels, catalase activity and apoptosis in ·OH-treated carp erythrocytes were equivalent to or stronger than those of BHT. Moreover, these results indicated that the inhibition order of EGbs on the generation of ROS and oxidation of cellular components in fish erythrocytes approximately agreed with that for the food and feed materials tested above. And, the antioxidative and anti-apoptotic effects of EGbs were

  15. ABO Blood Groups Influence Macrophage-mediated Phagocytosis of Plasmodium falciparum-infected Erythrocytes

    Science.gov (United States)

    Branch, Donald R.; Hult, Annika K.; Olsson, Martin L.; Liles, W. Conrad; Cserti-Gazdewich, Christine M.; Kain, Kevin C.

    2012-01-01

    Erythrocyte polymorphisms associated with a survival advantage to Plasmodium falciparum infection have undergone positive selection. There is a predominance of blood group O in malaria-endemic regions, and several lines of evidence suggest that ABO blood groups may influence the outcome of P. falciparum infection. Based on the hypothesis that enhanced innate clearance of infected polymorphic erythrocytes is associated with protection from severe malaria, we investigated whether P. falciparum-infected O erythrocytes are more efficiently cleared by macrophages than infected A and B erythrocytes. We show that human macrophages in vitro and mouse monocytes in vivo phagocytose P. falciparum-infected O erythrocytes more avidly than infected A and B erythrocytes and that uptake is associated with increased hemichrome deposition and high molecular weight band 3 aggregates in infected O erythrocytes. Using infected A1, A2, and O erythrocytes, we demonstrate an inverse association of phagocytic capacity with the amount of A antigen on the surface of infected erythrocytes. Finally, we report that enzymatic conversion of B erythrocytes to type as O before infection significantly enhances their uptake by macrophages to observed level comparable to that with infected O wild-type erythrocytes. These data provide the first evidence that ABO blood group antigens influence macrophage clearance of P. falciparum-infected erythrocytes and suggest an additional mechanism by which blood group O may confer resistance to severe malaria. PMID:23071435

  16. Experiment study and FEM simulation on erythrocytes under linear stretching of optical micromanipulation

    Science.gov (United States)

    Liu, Ying; Song, Huadong; Zhu, Panpan; Lu, Hao; Tang, Qi

    2017-08-01

    The elasticity of erythrocytes is an important criterion to evaluate the quality of blood. This paper presents a novel research on erythrocytes' elasticity with the application of optical tweezers and the finite element method (FEM) during blood storage. In this work, the erythrocytes with different in vitro times were linearly stretched by trapping force using optical tweezers and the time dependent elasticity of erythrocytes was investigated. The experimental results indicate that the membrane shear moduli of erythrocytes increased with the increasing in vitro time, namely the elasticity was decreasing. Simultaneously, an erythrocyte shell model with two parameters (membrane thickness h and membrane shear modulus H) was built to simulate the linear stretching states of erythrocytes by the FEM, and the simulations conform to the results obtained in the experiment. The evolution process was found that the erythrocytes membrane thicknesses were decreasing. The analysis assumes that the partial proteins and lipid bilayer of erythrocyte membrane were decomposed during the in vitro preservation of blood, which results in thin thickness, weak bending resistance, and losing elasticity of erythrocyte membrane. This study implies that the FEM can be employed to investigate the inward mechanical property changes of erythrocyte in different environments, which also can be a guideline for studying the erythrocyte mechanical state suffered from different diseases.

  17. A flexible infrared sensor for tissue oximetry

    DEFF Research Database (Denmark)

    Petersen, Søren Dahl; Thyssen, Anders; Engholm, Mathias

    2013-01-01

    We present a flexible infrared sensor for use in tissue oximetry with the aim of treating prematurely born infants. The sensor will detect the oxygen saturation in brain tissue through near infrared spectroscopy. The sensor itself consists of several individual silicon photo detectors fully...

  18. Response behaviour of oxygen sensing solid electrolytes

    NARCIS (Netherlands)

    Winnubst, Aloysius J.A.; Scharenborg, A.H.A.; Burggraaf, A.J.

    1985-01-01

    The response time (t r) after a step change in oxygen partial pressure was investigated for some solid electrolytes used in Nernst type oxygen sensors. The electrolyte as well as the (porous) electrode material affect the value oft r. Stabilized Bi2O3 materials exhibit slower response rates (largert

  19. Associations of erythrocyte fatty acid patterns with insulin resistance

    Science.gov (United States)

    Background: Synergistic and/or additive effects on cardiometabolic risk may be missed by examining individual fatty acids (FA). A pattern analysis may be a more useful approach. As well, it remains unclear whether erythrocyte fatty acid composition relates to insulin resistance among Hispanic/Latino...

  20. Fragmentation of Human Erythrocyte Actin following Exposure to Hypoxia

    Czech Academy of Sciences Publication Activity Database

    Risso, A.; Santamaria, B.; Pistarino, E.; Cosulich, M. E.; Pompach, Petr; Bezouška, Karel; Antonutto, G.

    2010-01-01

    Roč. 123, č. 1 (2010), s. 6-13 ISSN 0001-5792 Institutional research plan: CEZ:AV0Z50200510 Keywords : beta-Actin * Erythrocytes * Hypoxia Subject RIV: EE - Microbiology, Virology Impact factor: 1.316, year: 2010

  1. Erythrocyte membrane modified janus polymeric motors for thrombus therapy

    NARCIS (Netherlands)

    Shao, Jingxin; Abdelghani, Mona; Shen, Guizhi; Cao, Shoupeng; Williams, David S.; van Hest, Jan C.M.

    2018-01-01

    We report the construction of erythrocyte membrane-cloaked Janus polymeric motors (EM-JPMs) which are propelled by near-infrared (NIR) laser irradiation and are successfully applied in thrombus ablation. Chitosan (a natural polysaccharide with positive charge, CHI) and heparin (glycosaminoglycan

  2. Determination of molecular species of lecithin from erythrocytes and plasma

    NARCIS (Netherlands)

    Golde, L.M.G. van; Tomasi, V.; Deenen, L.L.M. van

    The molecular species of lecithin from erythrocyte and plasma of man and rabbit were determined after conversion of the lecithins into diglycerides by means of hydrolysis with phospholipase C. The resultant diglycerides were separated by thin-layer chromatography on silica impregnated with silver

  3. Erythrocyte antioxidant protection of rose hips (Rosa spp.).

    Science.gov (United States)

    Widén, C; Ekholm, A; Coleman, M D; Renvert, S; Rumpunen, K

    2012-01-01

    Rose hips are popular in health promoting products as the fruits contain high content of bioactive compounds. The aim of this study was to investigate whether health benefits are attributable to ascorbic acid, phenols, or other rose-hip-derived compounds. Freeze-dried powder of rose hips was preextracted with metaphosphoric acid and the sample was then sequentially eluted on a C(18) column. The degree of amelioration of oxidative damage was determined in an erythrocyte in vitro bioassay by comparing the effects of a reducing agent on erythrocytes alone or on erythrocytes pretreated with berry extracts. The maximum protection against oxidative stress, 59.4 ± 4.0% (mean ± standard deviation), was achieved when incubating the cells with the first eluted meta-phosphoric extract. Removal of ascorbic acid from this extract increased the protection against oxidative stress to 67.9 ± 1.9%. The protection from the 20% and 100% methanol extracts was 20.8 ± 8.2% and 5.0 ± 3.2%, respectively. Antioxidant uptake was confirmed by measurement of catechin by HPLC-ESI-MS in the 20% methanol extract. The fact that all sequentially eluted extracts studied contributed to protective effects on the erythrocytes indicates that rose hips contain a promising level of clinically relevant antioxidant protection.

  4. Erythrocyte indices and serum biochemical constituents of broiler ...

    African Journals Online (AJOL)

    One hundred and twenty (120) four weeks old Ross breed broiler finisher birds were used to study the effect of feeding maggot meal as a replacement for fish meal on erythrocyte indices and serum biochemical constituents. The birds were divided into 5 treatment groups identified as T1, T2, T3 , T4 and T5 with 24 birds per ...

  5. The role of inorganic phosphate in intact human erythrocytes

    International Nuclear Information System (INIS)

    Nishiguchi, Eiko; Umeda, Masahiro.

    1988-01-01

    The role of inorganic phosphate in intact human erythrocytes was investigated by phosphorus-31 nuclear magnetic resonance ( 31 P NMR). When erythrocytes stored for 5 weeks were incubated at 37 deg C, pH 7.4, in medium containing 2 mM adenine and 10 mM inosine, with or without 5 mM glucose, a substance of around 4 ppm, as assessed by 31 P NMR chemical shift, was detected in the mixture. However, this substance disappeared by the addition of inorganic phosphate. When erythrocytes stored for 4 weeks in acid citrate dextrose (ACD) solution were incubated with 2 mM adenine, 10 mM inosine, 5 mM glucose, 50 mM inorganic phosphate and 10 mM pyruvate at 37 deg C, pH 7.4, the 2,3-DPG level increased gradually, whereas the ATP level initially increased and then decreased. Intracellular inorganic phosphate appeared to be used for the synthesis of ATP and 2,3-DPG during the first 30 min. of the reaction. These results suggests that the inorganic phosphate accelerates glycolysis by increasing the activity of glycolytic enzymes rather than its direct involvement in synthesizing organic phosphorus compounds in stored erythrocytes. The results also suggests that the reserve energy from ATP synthesis is not sufficient for the synthesis of 2,3-DPG. (author)

  6. Erythrocytes and von Willebrand factor in venous thrombosis

    NARCIS (Netherlands)

    Smeets, M.W.J.

    2018-01-01

    Venous thromboembolism represents the third leading vascular disease after myocardial infarction and stroke. Erythrocytes, the most abundant cells in venous thrombi, were thought to be innocent bystanders that become tangled up in the fibrin mesh of venous thrombi. However, this thesis describes

  7. Erythrocyte Osmotic Fragility and Excitability Score in Rabbit fed ...

    African Journals Online (AJOL)

    olayemitoyin

    protect cells against oxidative stress in rats (Wang et al., 2000) and ... method, total red blood cell (RBC) count, total leukocyte (WBC) count .... maturative stages of the erythroblast (pluripotent stem cells) involved in cell formation (Kaur and. Kapoor, 2005). ... effect of zinc on chlorpyrifos- induced erythrocyte fragility in wistar ...

  8. Phosphorylation of intact erythrocytes in human muscular dystrophy

    International Nuclear Information System (INIS)

    Johnson, R.M.; Nigro, M.

    1986-01-01

    The uptake of exogenous 32 Pi into the membrane proteins of intact erythrocytes was measured in 8 patients with Duchenne muscular dystrophy. No abnormalities were noted after autoradiographic analysis. This contrasts with earlier results obtained when isolated membranes were phosphorylated with gamma-[ 32 P]ATP, and suggests a possible reinterpretation of those experiments

  9. Delayed effects of radiation on enzymes in erythrocytes

    International Nuclear Information System (INIS)

    Li Jinying; Zhang Weiping; Liu Benti

    1998-01-01

    Objective: To study the delayed effects of radiation on the enzymes in erythrocytes. Methods: The activity of 8 enzymes, related glycolysis, hexose monophosphate shunt, nucleotide metabolism, redox reaction and esterase in erythrocytes of five patients with bone marrow form of acute radiation sickness (ARS) were assayed at 1,2,3 and 6 years after exposure to 60 Co radiation. Results: The decreased activities of glucose-6-phosphate dehydrogenase (G6PD), pyruvate kinase (PK), NADH-methemoglobin reductase (MR) during the stage of crisis and of acetylcholinesterase (ACE) during the stage of convalescence were recovered to varying extent, whereas the lowered activities of the first three enzymes in some cases remained unchanged. There was no correlation between the enzyme activity and the radiation dose as well as the age of the patients. Conclusion: It is demonstrated that the delayed effects of radiation damage to erythrocyte enzymes are most significant in PK of glycolysis, G6PD of hexose monophosphate shunt and MR of redox reaction. It is suggested that the genes related to the synthesis of erythrocyte enzymes may be damaged by radiation

  10. Erythrocyte membrane fatty acids in multiple sclerosis patients and ...

    African Journals Online (AJOL)

    The risk of developing multiple sclerosis (MS) is associated with increased dietary intake of saturated fatty acids. For many years it has been suspected that this disease might be associated with an imbalance between unsaturated and saturated fatty acids. We determined erythrocyte membrane fatty acids levels in Hot ...

  11. A review on radiation damage of erythrocyte membranes

    International Nuclear Information System (INIS)

    Wang Junling; Wang Weidong; Qin Guangyong

    2007-01-01

    Biomembrane has very important biological function. Its damage will seriously disturb the directivity, the orderly nature and coordination of cell metabolism, and finally causes the cell death. This paper reviewed the effects of radiation damage on erythrocyte membrane in membrane composition, membrane function and oxidation resistance system. (authors)

  12. Erythrocyte osmotic fragility of pigs administered ascorbic acid and ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-11

    Jan 11, 2010 ... procedure, were taken early in the morning a day before ... transportation and the difference in the post-transportation values was higher (P < 0.05) in experimental ..... erythrocytes in sedentary rats but not exercise-trained rats.

  13. Erratum Detergent-resistant membranes in human erythrocytes and ...

    Indian Academy of Sciences (India)

    Unknown

    Figure 3. Immunodetection of flotillin-2 and band 3 in DRMs isolated from erythrocyte ghosts by various treatments. Flotillin-2. (left) and band 3 (right) Western blotting in ten fractions of 0⋅5 ml each, obtained from the sucrose gradients described in figure 2 and numbered from top to bottom. Flotillin-2 is enriched in DRMs ...

  14. Alterations of thalassemic erythrocytes detected by wavelet entropy

    Science.gov (United States)

    Korol, A. M.; Rasia, R. J.; Rosso, O. A.

    2007-02-01

    A quantitative analysis of erythrocytes deformation under shear stress (the viscoelastic properties) observed on healthy donors as well as thalassemic patients are made by means of the normalized total wavelet entropy (NTWS). The results suggest that NTWS quantifier could be useful for characterizing pathological disturbances for the sake of clinical treatment.

  15. Apolipoprotein M mediates sphingosine-1-phosphate efflux from erythrocytes

    DEFF Research Database (Denmark)

    Christensen, Pernille M.; Bosteen, Markus H.; Hajny, Stefan

    2017-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid implicated in e.g. angiogenesis, lymphocyte trafficking, and endothelial barrier function. Erythrocytes are a main source of plasma S1P together with platelets and endothelial cells. Apolipoprotein M (apoM) in HDL carries 70% of plasma S1P, whereas...... 30% is carried by albumin. The current aim was to investigate the role of apoM in export of S1P from human erythrocytes. Erythrocytes exported S1P more efficiently to HDL than to albumin, particularly when apoM was present in HDL. In contrast, export of sphingosine to HDL was unaffected...... by the presence of apoM. The specific ability of apoM to promote export of S1P was independent of apoM being bound in HDL particles. Treatment with MK-571, an inhibitor of the ABCC1 transporter, effectively reduced export of S1P from human erythrocytes to apoM, whereas the export was unaffected by inhibitors...

  16. Dyslipidemia, altered erythrocyte fatty acids and selenium are ...

    African Journals Online (AJOL)

    Venous blood sample was drawn from all subjects and erythrocytes separated for the determination of fatty acids. Plasma lipids, selenium and vitamin E levels were also measured. There were no differences in BMI, weight and height among the three groups except for systolic BP that was lower in VD (148.3±41.8mmHg) ...

  17. Changes in erythrocyte ATPase activity under different pathological ...

    African Journals Online (AJOL)

    Changes in erythrocyte ATPase activity under different pathological conditions. Ali A Kherd, Nawal Helmi, Khadijah Saeed Balamash, Taha A Kumosani, Shareefa A AL-Ghamdi, Qari M, Etimad A Huwait, Soonham S Yaghmoor, Alaama Nabil, Maryam A AL-Ghamdi, Said S Moselhy ...

  18. Improved Erythrocyte Osmotic Fragility and Packed Cell Volume ...

    African Journals Online (AJOL)

    Improved Erythrocyte Osmotic Fragility and Packed Cell Volume following administration of Aloe barbadensis Juice Extract in Rats. ... Abstract. Aloe barbadensis is a popular house plant that has a long history of a multipurpose folk remedy. ... Keywords: osmotic fragility, packed cell volume, haemoglobin, Aloe vera ...

  19. Effect of Aflatoxin B1 - contaminated feed on goat erythrocyte ...

    African Journals Online (AJOL)

    ... action was concentration-dependent, typical of a saturation kinetic effect. The degree of stimulation varied from 20% to more than 90% between the lowest (0.1 M) and highest (1000 M) contentrations. AFB1 induced changes in the apparent kinetic parameters, Km and Vmax, of the erythrocyte membrane-bound enzyme.

  20. NMR studies of transmembrane electron transport in human erythrocytes

    International Nuclear Information System (INIS)

    Kennett, E.C.; Bubb, W.A.; Kuchel, P.W.

    2002-01-01

    Full text: Electron transport systems exist in the plasma membranes of all cells. These systems appear to play a role in cell growth and proliferation, intracellular signalling, hormone responses, apoptotic events, cell defence and perhaps most importantly they enable the cell to respond to changes in the redox state of both the intra- and extracellular environments. Previously, 13 C NMR has been used to study transmembrane electron transport in human erythrocytes, specifically the reduction of extracellular 13 C-ferricyanide. NMR is a particularly useful tool for studying such systems as changes in the metabolic state of the cell can be observed concomitantly with extracellular reductase activity. We investigated the oxidation of extracellular NADH by human erythrocytes using 1 H and 31 P NMR spectroscopy. Recent results for glucose-starved human erythrocytes indicate that, under these conditions, extracellular NADH can be oxidised at the plasma membrane with the electron transfer across the membrane resulting in reduction of intracellular NAD + . The activity is inhibited by known trans-plasma membrane electron transport inhibitors (capsaicin and atebrin) and is unaffected by inhibition of the erythrocyte Band 3 anion transporter. These results suggest that electron import from extracellular NADH allows the cell to re-establish a reducing environment after the normal redox balance is disturbed

  1. Role of aminotransferases in glutamate metabolism of human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Ellinger, James J. [University of Wisconsin-Madison, Department of Biochemistry (United States); Lewis, Ian A. [Princeton University, Lewis-Sigler Institute for Integrative Genomics (United States); Markley, John L., E-mail: markley@nmrfam.wisc.edu [University of Wisconsin-Madison, Department of Biochemistry (United States)

    2011-04-15

    Human erythrocytes require a continual supply of glutamate to support glutathione synthesis, but are unable to transport this amino acid across their cell membrane. Consequently, erythrocytes rely on de novo glutamate biosynthesis from {alpha}-ketoglutarate and glutamine to maintain intracellular levels of glutamate. Erythrocytic glutamate biosynthesis is catalyzed by three enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamine aminohydrolase (GA). Although the presence of these enzymes in RBCs has been well documented, the relative contributions of each pathway have not been established. Understanding the relative contributions of each biosynthetic pathway is critical for designing effective therapies for sickle cell disease, hemolytic anemia, pulmonary hypertension, and other glutathione-related disorders. In this study, we use multidimensional {sup 1}H-{sup 13}C nuclear magnetic resonance (NMR) spectroscopy and multiple reaction mode mass spectrometry (MRM-MS) to measure the kinetics of de novo glutamate biosynthesis via AST, ALT, and GA in intact cells and RBC lysates. We show that up to 89% of the erythrocyte glutamate pool can be derived from ALT and that ALT-derived glutamate is subsequently used for glutathione synthesis.

  2. Mercury chloride-induced oxidative stress in human erythrocytes ...

    African Journals Online (AJOL)

    ONOS

    2010-01-25

    Jan 25, 2010 ... Mercury can exist in the environment as metal, as monovalent and divalent salts and as organomercurials, one of the most important of which is mercuric chloride (HgCl2). It has been shown to induce oxidative stress in erythrocytes through the generation of free radicals and alteration of the.

  3. Changes in erythrocytic deformability and plasma viscosity in neonatal ictericia.

    Science.gov (United States)

    Bonillo-Perales, A; Muñoz-Hoyos, A; Martínez-Morales, A; Molina-Carballo, A; Uberos-Fernández, J; Puertas-Prieto, A

    1999-01-01

    We studied 45 full-term newborns divided into 3 groups. Group 1: 17 newborns with bilirubin ictericia (bilirubin 11-20 mg/dL) and Group 3: 10 newborns with moderate hemolytic ictericia needing exchange transfusion. The following were studied: erythrocytic deformability, plasma viscosity, plasmatic osmolarity, seric bilirubin, bilirubin/albumin ratio, free fatty acids and corpuscular volume of the erythrocytes. In full-term newborns, the following are risk factors for increased erythrocytic rigidity: neonatal hemolytic illness (p = 0.004, odds ratio: 7.02), increases in total bilirubin (p = 0.02, odds ratio: 4.3) and increases in the bilirubin/albumin ratio (p = 0.025, odds ratio: 4.25). Furthermore, the most important risk factor for high plasma viscosity is also neonatal hemolytic illness (p = 0.01, odds ratio: 2.30). The role of total bilirubin is also important (p = 0.09, odds ratio: 2.10), while that of the bilirubin/albumin ratio (p = 0.012, NS) is less so. The greater the hemolysis, the greater the erythrocytic rigidity and plasma viscosity (p ictericia, hemolytic illness and increases in the bilirubin/albumin ratio are accompanied by rheological alterations that could affect cerebral microcirculation and cause a neurological deficit not exclusively related to the levels of bilirubin in plasma.

  4. Effect of garlic's mode of administration on erythrocytes and plasma ...

    African Journals Online (AJOL)

    With regard to erythrocytes parameters, p.o. garlic treatment was found to have beneficial effects as it increased hemoglobin and hematocrit levels. Garlic i.p. treatment showed detrimental activity as it decreased these parameters. Our results reveal that garlic administered by p.o. does not involve any significant variation on ...

  5. Measurement of oxygen transfer from air into organic solvents

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias

    2016-01-01

    biological reactions require the supply of oxygen, most normally from air. However, reliable on-line measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due limitations in the current analytical methods. Results...... applications). Subsequently, we measured the oxygen transfer rates from air into these organic solvents. Conclusion The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen...... For the first time, we demonstrate on-line oxygen measurements in non-aqueous media using a novel optical sensor. The sensor was used to measure oxygen concentration in various organic solvents including toluene, THF, isooctane, DMF, heptane and hexane (which have all been shown suitable for several biological...

  6. Biophysical Properties of Irradiated Erythrocytes and Role of Antioxidants

    International Nuclear Information System (INIS)

    Eman Mohammed Elbakrawy, E.M.

    2010-01-01

    Irradiation of blood and blood components with gamma-irradiation is recommended for the inactivation of T-lymphocytes and prevention of transfusion-associated graft versus host diseases. The aim of the present work is to ensure that the currently applied irradiation dose 25 Gy is a safe dose based on the study of the electrical behavior, rheological properties, membrane solubilization, membrane hemolysis and scanning electron microscope of stored erythrocytes. In addition it aims to study the possibility of increasing the irradiation doses to 50 and 100 Gy. Moreover Alpha lipoic acid (a potent natural antioxidant) was added to the stored erythrocytes before irradiation for radioprotection. Irradiation of erythrocytes with 25 Gy did not show significant changes for the calculated dielectric parameters. However, increasing the irradiation doses resulted in significant decrease in the calculated dielectric parameters reflecting the damaging effects of radiation on the membrane structure. The obtained results showed that α lipoic acid can play an important role in minimizing the radiation-induced damage to the erythrocytes and conserve their electrical properties. There were non-significant changes in viscosity after exposure to 25 Gy, while a significant increase at 50 Gy and a significant decrease at 100 Gy were observed. The study found that α lipoic acid (ALA) resulted in non-significant change in viscosity after exposure to 50 Gy and 100 Gy. A significant increase in the yield stress was observed after exposure to 25 and 50 Gy while at 100 Gy, the yield stress showed a remarkable decrease. Addition of .-lipoic acid before irradiation resulted in non-significant changes in the yield stress at doses 25, 50, 100 Gy.The obtained results of the average membrane solubilization (D 50 ) and the average membrane hemolysis (H 50 ) showed non-significant change at 25 Gy; while an observable decrease was observed at 50 Gy and 100 Gy. The addition of lipoic acid did not

  7. Taste sensor; Mikaku sensor

    Energy Technology Data Exchange (ETDEWEB)

    Toko, K. [Kyushu University, Fukuoka (Japan)

    1998-03-05

    This paper introduces a taste sensor having a lipid/polymer membrane to work as a receptor of taste substances. The paper describes the following matters: this sensor uses a hollow polyvinyl chloride rod filled with KCl aqueous solution, and placed with silver and silver chloride wires, whose cross section is affixed with a lipid/polymer membrane as a lipid membrane electrode to identify taste from seven or eight kinds of response patterns of electric potential output from the lipid/polymer membrane; measurements of different substances presenting acidic taste, salty taste, bitter taste, sweet taste and flavor by using this sensor identified clearly each taste (similar response is shown to a similar taste even if the substances are different); different responses are indicated on different brands of beers; from the result of measuring a great variety of mineral waters, a possibility was suggested that this taste sensor could be used for water quality monitoring sensors; and application of this taste sensor may be expected as a maturation control sensor for Japanese sake (wine) and miso (bean paste) manufacturing. 2 figs., 1 tab.

  8. Plasmodium falciparum-infected erythrocytes do not adhere well to C32 melanoma cells or CD36 unless rosettes with uninfected erythrocytes are first disrupted.

    OpenAIRE

    Handunnetti, S M; Hasler, T H; Howard, R J

    1992-01-01

    Plasmodium falciparum malaria parasites modify the human erythrocytes in which they grow so that some parasitized erythrocytes (PE) can cytoadhere (C+) to host vascular endothelial cells or adhere in rosettes (R+) to uninfected erythrocytes. These C+ and R+ adherence properties of PE appear to mediate much of the pathogenesis of severe malaria infections, in part by blocking blood flow in microvessels. From one parasite strain, PE were selected in vitro for C+ R+ or C+ R- adherence properties...

  9. Stimulation of erythrocyte phosphatidylserine exposure by mercury ions

    International Nuclear Information System (INIS)

    Eisele, Kerstin; Lang, Philipp A.; Kempe, Daniela S.; Klarl, Barbara A.; Niemoeller, Olivier; Wieder, Thomas; Huber, Stephan M.; Duranton, Christophe; Lang, Florian

    2006-01-01

    The sequelae of mercury intoxication include induction of apoptosis. In nucleated cells, Hg 2+ -induced apoptosis involves mitochondrial damage. The present study has been performed to elucidate effects of Hg 2+ in erythrocytes which lack mitochondria but are able to undergo apoptosis-like alterations of the cell membrane. Previous studies have documented that activation of a Ca 2+ -sensitive erythrocyte scramblase leads to exposure of phosphatidylserine at the erythrocyte surface, a typical feature of apoptotic cells. The erythrocyte scramblase is activated by osmotic shock, oxidative stress and/or energy depletion which increase cytosolic Ca 2+ activity and/or activate a sphingomyelinase leading to formation of ceramide. Ceramide sensitizes the scramblase to Ca 2+ . The present experiments explored the effect of Hg 2+ ions on erythrocytes. Phosphatidylserine exposure after mercury treatment was estimated from annexin binding as determined in FACS analysis. Exposure to Hg 2+ (1 μM) indeed significantly increased annexin binding from 2.3 ± 0.5% (control condition) to 23 ± 6% (n = 6). This effect was paralleled by activation of a clotrimazole-sensitive K + -selective conductance as measured by patch-clamp recordings and by transient cell shrinkage. Further experiments revealed also an increase of ceramide formation by ∼66% (n = 7) after challenge with mercury (1 μM). In conclusion, mercury ions activate a clotrimazole-sensitive K + -selective conductance leading to transient cell shrinkage. Moreover, Hg 2+ increases ceramide formation. The observed mechanisms could similarly participate in the triggering of apoptosis in nucleated cells by Hg 2+

  10. Triggering of Erythrocyte Cell Membrane Scrambling by Emodin

    Directory of Open Access Journals (Sweden)

    Morena Mischitelli

    2016-11-01

    Full Text Available Background/Aims: The natural anthraquinone derivative emodin (1,3,8-trihydroxy-6-methylanthraquinone is a component of several Chinese medicinal herbal preparations utilized for more than 2000 years. The substance has been used against diverse disorders including malignancy, inflammation and microbial infection. The substance is effective in part by triggering suicidal death or apoptosis. Similar to apoptosis of nucleated cells erythrocytes may enter suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the triggering of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and ceramide. The present study aimed to test, whether emodin induces eryptosis and, if so, to elucidate underlying cellular mechanisms. Methods: Phosphatidylserine abundance at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: Exposure of human erythrocytes for 48 hours to emodin (≥ 10 µM significantly increased the percentage of annexin-V-binding cells, and at higher concentrations (≥ 50 µM significantly increased forward scatter. Emodin significantly increased Fluo3-fluorescence (≥ 10 µM, DCFDA fluorescence (75 µM and ceramide abundance (75 µM. The effect of emodin on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca2+. Conclusions: Emodin triggers phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to stimulation of Ca2+ entry and paralleled by oxidative stress and ceramide appearance at the erythroctye surface.

  11. Flow cytometric determination of osmotic behaviour of animal erythrocytes toward their engineering for drug delivery

    Directory of Open Access Journals (Sweden)

    Kostić Ivana T.

    2015-01-01

    Full Text Available Despite the fact that the methods based on the osmotic properties of the cells are the most widely used for loading of drugs in human and animal erythrocytes, data related to the osmotic properties of erythrocytes derived from animal blood are scarce. This work was performed with an aim to investigate the possibility of use the flow cytometry as a tool for determination the osmotic behaviour of porcine and bovine erythrocytes, and thus facilitate the engineering of erythrocytes from animal blood to be drug carriers. The method of flow cytometry successfully provided the information about bovine and porcine erythrocyte osmotic fragility, and made the initial steps in assessment of erythrocyte shape in a large number of erythrocytes. Although this method is not able to confirm the swelling of pig erythrocytes, it indicated to the differences in pig erythrocytes that had basic hematological parameters inside and outside the reference values. In order to apply/use the porcine and bovine erythrocytes as drug carriers, the method of flow cytometry, confirming the presence of osmotically different fractions of red blood cells, indicated that various amounts of the encapsulated drug in porcine and bovine erythrocytes can be expected.

  12. Erythrocyte membrane ATPase and calcium pumping activities in porcine malignant hyperthermia

    International Nuclear Information System (INIS)

    Thatte, H.S.; Mickelson, J.R.; Addis, P.B.; Louis, C.F.

    1987-01-01

    To investigate possible abnormalities in erythrocyte membrane enzyme activities in the pharmacogenetic disorder MH, membrane ATPase activities have been examined in erythrocyte ghosts prepared from red blood cells of MHS and normal swine. While no differences were noted in Mg2+-ATPase activities, the (Na+, K+)-ATPase activity of MHS erythrocyte ghosts was less than that of normal ghosts. Ca2+-ATPase activity exhibited low- and high-affinity Ca2+-binding sites in both types of erythrocyte ghost. While the Km for Ca2+ was greater for normal than for MHS erythrocyte ghosts at the high-affinity Ca2+-binding site, the reverse was true at the low-affinity Ca2+-binding site. Irrespective of the type of calcium binding site occupied, the Vmax for normal erythrocyte ghost Ca2+-ATPase activity was greater than that for MHS ghosts. In the presence of calmodulin, there was now no difference between MHS and normal erythrocyte ghosts in either the Km for Ca2+ or the Vmax of the Ca2+-ATPase activity. To determine if the calcium pumping activity of intact MHS and normal pig erythrocytes differed, calcium efflux from the 45 Ca-loaded erythrocytes was determined; this activity was significantly greater for MHS than for normal erythrocytes. Thus, the present study confirms that there are abnormalities in the membranes of MHS pig red blood cells. However, we conclude that these abnormalities are unlikely to result in an impaired ability of MHS erythrocytes to regulate their cytosolic Ca2+ concentration

  13. Mapping oxygen concentration in the awake mouse brain

    Science.gov (United States)

    Lyons, Declan G; Parpaleix, Alexandre; Roche, Morgane; Charpak, Serge

    2016-01-01

    Although critical for brain function, the physiological values of cerebral oxygen concentration have remained elusive because high-resolution measurements have only been performed during anesthesia, which affects two major parameters modulating tissue oxygenation: neuronal activity and blood flow. Using measurements of capillary erythrocyte-associated transients, fluctuations of oxygen partial pressure (Po2) associated with individual erythrocytes, to infer Po2 in the nearby neuropil, we report the first non-invasive micron-scale mapping of cerebral Po2 in awake, resting mice. Interstitial Po2 has similar values in the olfactory bulb glomerular layer and the somatosensory cortex, whereas there are large capillary hematocrit and erythrocyte flux differences. Awake tissue Po2 is about half that under isoflurane anesthesia, and within the cortex, vascular and interstitial Po2 values display layer-specific differences which dramatically contrast with those recorded under anesthesia. Our findings emphasize the importance of measuring energy parameters non-invasively in physiological conditions to precisely quantify and model brain metabolism. DOI: http://dx.doi.org/10.7554/eLife.12024.001 PMID:26836304

  14. A robust mass spectrometry method for rapid profiling of erythrocyte ghost membrane proteomes.

    Science.gov (United States)

    Fye, Haddy K S; Mrosso, Paul; Bruce, Lesley; Thézénas, Marie-Laëtitia; Davis, Simon; Fischer, Roman; Rwegasira, Gration L; Makani, Julie; Kessler, Benedikt M

    2018-01-01

    Red blood cell (RBC) physiology is directly linked to many human disorders associated with low tissue oxygen levels or anemia including chronic obstructive pulmonary disease, congenital heart disease, sleep apnea and sickle cell anemia. Parasites such as Plasmodium spp. and phylum Apicomplexa directly target RBCs, and surface molecules within the RBC membrane are critical for pathogen interactions. Proteomics of RBC membrane 'ghost' fractions has therefore been of considerable interest, but protocols described to date are either suboptimal or too extensive to be applicable to a larger set of clinical cohorts. Here, we describe an optimised erythrocyte isolation protocol from blood, tested for various storage conditions and explored using different fractionation conditions for isolating ghost RBC membranes. Liquid chromatography mass spectrometry (LC-MS) analysis on a Q-Exactive Orbitrap instrument was used to profile proteins isolated from the comparative conditions. Data analysis was run on the MASCOT and MaxQuant platforms to assess their scope and diversity. The results obtained demonstrate a robust method for membrane enrichment enabling consistent MS based characterisation of > 900 RBC membrane proteins in single LC-MS/MS analyses. Non-detergent based membrane solubilisation methods using the tissue and supernatant fractions of isolated ghost membranes are shown to offer effective haemoglobin removal as well as diverse recovery including erythrocyte membrane proteins of high and low abundance. The methods described in this manuscript propose a medium to high throughput framework for membrane proteome profiling by LC-MS of potential applicability to larger clinical cohorts in a variety of disease contexts.

  15. Plasmodium falciparum glutamate dehydrogenase a is dispensable and not a drug target during erythrocytic development

    LENUS (Irish Health Repository)

    Storm, Janet

    2011-07-14

    Abstract Background Plasmodium falciparum contains three genes encoding potential glutamate dehydrogenases. The protein encoded by gdha has previously been biochemically and structurally characterized. It was suggested that it is important for the supply of reducing equivalents during intra-erythrocytic development of Plasmodium and, therefore, a suitable drug target. Methods The gene encoding the NADP(H)-dependent GDHa has been disrupted by reverse genetics in P. falciparum and the effect on the antioxidant and metabolic capacities of the resulting mutant parasites was investigated. Results No growth defect under low and elevated oxygen tension, no up- or down-regulation of a number of antioxidant and NADP(H)-generating proteins or mRNAs and no increased levels of GSH were detected in the D10Δgdha parasite lines. Further, the fate of the carbon skeleton of [13C] labelled glutamine was assessed by metabolomic studies, revealing no differences in the labelling of α-ketoglutarate and other TCA pathway intermediates between wild type and mutant parasites. Conclusions First, the data support the conclusion that D10Δgdha parasites are not experiencing enhanced oxidative stress and that GDHa function may not be the provision of NADP(H) for reductive reactions. Second, the results imply that the cytosolic, NADP(H)-dependent GDHa protein is not involved in the oxidative deamination of glutamate but that the protein may play a role in ammonia assimilation as has been described for other NADP(H)-dependent GDH from plants and fungi. The lack of an obvious phenotype in the absence of GDHa may point to a regulatory role of the protein providing glutamate (as nitrogen storage molecule) in situations where the parasites experience a limiting supply of carbon sources and, therefore, under in vitro conditions the enzyme is unlikely to be of significant importance. The data imply that the protein is not a suitable target for future drug development against intra-erythrocytic

  16. Calorimetric study on human erythrocyte glycolysis. Heat production in various metabolic conditions.

    Science.gov (United States)

    Minakami, S; de Verdier, C H

    1976-06-01

    The heat production of human erythrocytes was measured on a flow microcalorimeter with simultaneous analyses of lactate and other metabolites. The heat production connected with the lactate formation was about 17 kcal (71 kJ) per mol lactate formed which corresponded to the sum of heat production due to the formation of lactate from glucose and the heat production due to neutralization. The heat production rate increased as the pH of the suspension increased, corresponding to the increase in lactate formation. Glycolytic inhibitors such as fluoride and monoiodoacetate caused a decrease in the rate of heat production, whereas arsenate induced a large transient increase in heat production associated with a transient increase in lactate formation. Decrease in pyruvate concentration was usually associated with increase in heat production, although the decreased pyruvate concentration was coupled with formation of 2,3-bisphosphoglycerate. When inosine, dihydroxyacetone or D-glyceraldehyde was used as a substrate, an increase in the heat production rate was observed. Addition of methylene blue caused an oxygen uptake which was accompanied by a remarkable increase in heat production rate corresponding to about 160 kcal (670 kJ) per mol oxygen consumed. The value for heat production in red cells in the above-mentioned metabolic conditions was considered in relation to earlier known data on free energy and enthalpy changes of the different metabolic steps in the glycolytic pathway.

  17. Inhaled nitric oxide augments nitric oxide transport on sickle cell hemoglobin without affecting oxygen affinity

    OpenAIRE

    Gladwin, Mark T.; Schechter, Alan N.; Shelhamer, James H.; Pannell, Lewis K.; Conway, Deirdre A.; Hrinczenko, Borys W.; Nichols, James S.; Pease-Fye, Margaret E.; Noguchi, Constance T.; Rodgers, Griffin P.; Ognibene, Frederick P.

    1999-01-01

    Nitric oxide (NO) inhalation has been reported to increase the oxygen affinity of sickle cell erythrocytes. Also, proposed allosteric mechanisms for hemoglobin, based on S-nitrosation of β-chain cysteine 93, raise the possibilty of altering the pathophysiology of sickle cell disease by inhibiting polymerization or by increasing NO delivery to the tissue. We studied the effects of a 2-hour treatment, using varying concentrations of inhaled NO. Oxygen affinity, as measured by P50, did not respo...

  18. Examination of the calcium-erythrocyte membrane interactions

    International Nuclear Information System (INIS)

    Gardos, Gy.; Szasz, I.; Sarkadi, B.

    1979-01-01

    A review of the cation-transport mechanisms of human erythrocytes is given. The following experimental methods were applied: measurement of 45 Ca influx, 45 Ca efflux, 42 K influx, 42 K efflux, 22 Na efflux and determination of the activity of the Ca-ATP-ase enzyme. The increase of the intracellular Ca-level opens some specific K-channels, through which K is leaking out passively. The kinetics and the chemical nature of this K-transport are given in detail. On the other hand, Ca ions taken up are removed by active transport. Detailed data are given on the activity and specific inhibition of this Ca-pump. In human erythrocytes the pump is working with the stoichiometry of Ca:ATP=2. (L.E.)

  19. Purification and properties of enolase of human erythrocytes

    NARCIS (Netherlands)

    Hoorn, R.K.J.; Flikweert, J.P.; Staal, Gerard E.J.

    1974-01-01

    1. 1. Human erythrocyte enolase (2-phospho-D-glycerate hydrolyase, EC 4.2.1.11) was purified I000-fold. 2. 2. The pH-optimum was at pH 6.5. The molecular weight, estimated by gel filtration, was found to be 95,000 ± 5,000. 3. 3. Electrophoresis on agar-agarose at pH 8.5 and 6.4 showed only one

  20. Tirilazad mesylate protects stored erythrocytes against osmotic fragility.

    Science.gov (United States)

    Epps, D E; Knechtel, T J; Bacznskyj, O; Decker, D; Guido, D M; Buxser, S E; Mathews, W R; Buffenbarger, S L; Lutzke, B S; McCall, J M

    1994-12-01

    The hypoosmotic lysis curve of freshly collected human erythrocytes is consistent with a single Gaussian error function with a mean of 46.5 +/- 0.25 mM NaCl and a standard deviation of 5.0 +/- 0.4 mM NaCl. After extended storage of RBCs under standard blood bank conditions the lysis curve conforms to the sum of two error functions instead of a possible shift in the mean and a broadening of a single error function. Thus, two distinct sub-populations with different fragilities are present instead of a single, broadly distributed population. One population is identical to the freshly collected erythrocytes, whereas the other population consists of osmotically fragile cells. The rate of generation of the new, osmotically fragile, population of cells was used to probe the hypothesis that lipid peroxidation is responsible for the induction of membrane fragility. If it is so, then the antioxidant, tirilazad mesylate (U-74,006f), should protect against this degradation of stored erythrocytes. We found that tirilazad mesylate, at 17 microM (1.5 mol% with respect to membrane lecithin), retards significantly the formation of the osmotically fragile RBCs. Concomitantly, the concentration of free hemoglobin which accumulates during storage is markedly reduced by the drug. Since the presence of the drug also decreases the amount of F2-isoprostanes formed during the storage period, an antioxidant mechanism must be operative. These results demonstrate that tirilazad mesylate significantly decreases the number of fragile erythrocytes formed during storage in the blood bank.

  1. [Ratio of erythrocyte and plasma in massive blood transfusion].

    Science.gov (United States)

    Wen, Xian-Hui; Liu, Feng-Xia; Zhang, Jun-Hua; Gui, Rong

    2014-06-01

    This study was purposed to explore the suitable ratio between fresh frozen plasma and erythrocyte by retrospective analysis of coagulation in patients with massive blood transfusion. The clinical data of 151 cases with massive blood transfusion from January 2011 to January 2013 were analyzed retrospectively. According to coagulation, patients were divided into coagulation normal group (138 cases) and coagulation dysfunction group (13 cases). Based on the ratio of 1:1 of fresh frozen plasma and erythrocyte, the patients were divided into high plasma group(2:1), medium plasma group (1:1) and low plasma (blood transfusion. The results showed that prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) were prolonged, fibrinogen (FIB) level decreased significantly (all P blood transfusion 24 h; the high plasma and the medium plasma group of coagulation normal group had no significant changes in coagulation (P > 0.05); prothrombin time, activated partial thromboplastin time, thrombin time and fibrinogen level in the medium plasma and low plasma subgroup of coagulation dysfunction group after massive transfusion was still in abnormal levels (P > 0.05), coagulation function in high plasma subgroup was improved significantly (P blood transfusion, the ratio between fresh frozen plasma and erythrocyte is recommended to be 2:1 in patients of coagulation dysfunction in order to improve the patient's coagulation function and to reduce the incidence of adverse event, the ratio of fresh frozen plasma to erythrocyte is recommended to be 1:1 in patients with normal coagulation so as to reduce the dilutional coagulopathy and hypervolemia of blood.

  2. Effect of fluorozis on the erythrocyte antioxidant enzyme activity levels

    International Nuclear Information System (INIS)

    Akdogan, M.; YiImaz, D.; Yontem, M.; Kalei, S.; Kilic, I.

    2011-01-01

    While the flourine level of (drinking) water was higher than normal ranges in the center of Isparta region before 1995 year, this problematic situation is solved in later years. (However) the individuals who are staying in Yenice district are still expose to high levels of fluorine because of the usage of Andik spring water (3.8 mg/L flour level) as drinking water. In this study we aimed to investigate the harmful effect of floride on human erythrocytes via antioxidant defence system and lipid peroxidation. Therefore, we studied the activities of erythrocyte antioxidant enzymes such as Superoxide Dismutase (SOD), Glutathione Peroxidase (GSH-Px) and Catalase (CAT), and the level of erythrocyte Glutathione (GSH), thiobarbituric acid reactive substance (TBARS) and the level of urine floride in high floride exposed people (children, adult and elderly). The activities of SOD, GSH-Px and CAT and the level of GSH, TBARS and urine floride were higher in 3.8 mg/L floride exposed children (Group II) than 0.8 mg/L floride exposed control children (Group I) (p 0.05). The activities of SOD, GSH-Px and CAT were lower and the levels of TBARS and urine floride were higher in 3.8 mg/L floride exposed elderly people (Group VI) than 0.8 mg/L floride exposed control elderly people (Group V) (p 0.05). As a result we thought that increased SOD, GSH-Px and CAT activities in floride exposed children and adult people, decreased activities of these enzymes in floride exposed elderly people, and increased TBARS in all groups may indicate floride caused oxidative damage in erythrocytes. (author)

  3. The reference range of serum, plasma and erythrocyte magnesium

    Directory of Open Access Journals (Sweden)

    Suzanna Immanuel

    2006-12-01

    Full Text Available The interest in the clinical importance of serum magnesium level has just recently begun with the analysis and findings of abnormal magnesium level in cardiovascular, metabolic and neuromuscular disorder. Although the serum level does not reflect the body magnesium level, but currently, only serum magnesium determination is widely used. Erythrocyte magnesium is considered more sensitive than serum magnesium as it reflects intracellular magnesium status. According to NCCLS (National Committee for Clinical Laboratory Standards every laboratory is recommended to have its own reference range for the tests it performs, including magnesium determination. The reference range obtained is appropriate for the population and affected by the method and technique. This study aimed to find the reference range of serum and plasma magnesium and also intracellular magnesium i.e. erythrocyte magnesium by direct method, and compare the results of serum and plasma magnesium. Blood was taken from 114-blood donor from Unit Transfusi Darah Daerah (UTDD Budhyarto Palang Merah Indonesia (PMI DKI Jakarta, consisted of 57 male and 57 female, aged 17 – 65 years, clinically healthy according to PMI donor criteria. Blood was taken from blood set, collected into 4 ml vacuum tube without anticoagulant for serum magnesium determination and 3 ml vacuum tube with lithium heparin for determination of erythrocyte and plasma magnesium Determination of magnesium level was performed with clinical chemistry auto analyzer Hitachi 912 by Xylidil Blue method colorimetrically. This study showed no significant difference between serum and heparinized plasma extra cellular magnesium. The reference range for serum or plasma magnesium was 1.30 – 2.00 mEq/L and for erythrocyte magnesium was 4.46 - 7.10 mEq/L. (Med J Indones 2006; 15:229-35Keywords: Reference range, extracellular magnesium, intracellular magnesium

  4. The complete amino acid sequence of human erythrocyte diphosphoglycerate mutase.

    OpenAIRE

    Haggarty, N W; Dunbar, B; Fothergill, L A

    1983-01-01

    The complete amino acid sequence of human erythrocyte diphosphoglycerate mutase, comprising 239 residues, was determined. The sequence was deduced from the four cyanogen bromide fragments, and from the peptides derived from these fragments after digestion with a number of proteolytic enzymes. Comparison of this sequence with that of the yeast glycolytic enzyme, phosphoglycerate mutase, shows that these enzymes are 47% identical. Most, but not all, of the residues implicated as being important...

  5. Erythrocyte glucose-6-phosphate dehydrogenase from Brazilian opossum Didelphis marsupialis

    Directory of Open Access Journals (Sweden)

    Barretto O.C. de O.

    2006-01-01

    Full Text Available In a comparative study of erythrocyte metabolism of vertebrates, the specific activity of glucose-6-phosphate dehydrogenase (G6PD of the Brazilian opossum Didelphis marsupialis in a hemolysate was shown to be high, 207 ± 38 IU g-1 Hb-1 min-1 at 37ºC, compared to the human erythrocyte activity of 12 ± 2 IU g-1 Hb-1 min-1 at 37ºC. The apparent high specific activity of the mixture led us to investigate the physicochemical properties of the opossum enzyme. We report that reduced glutathione (GSH in the erythrocytes was only 50% higher than in human erythrocytes, a value lower than expected from the high G6PD activity since GSH is maintained in a reduced state by G6PD activity. The molecular mass, determined by G-200 Sephadex column chromatography at pH 8.0, was 265 kDa, which is essentially the same as that of human G6PD (260 kDa. The Michaelis-Menten constants (Km: 55 µM for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (Km: 3.3 µM were similar to those of the human enzyme (Km: 50-70 and Km: 2.9-4.4, respectively. A 450-fold purification of the opossum enzyme was achieved and the specific activity of the purified enzyme, 90 IU/mg protein, was actually lower than the 150 IU/mg protein observed for human G6PD. We conclude that G6PD after purification from the hemolysate of D. marsupialis does not have a high specific activity. Thus, it is quite probable that the red cell hyperactivity reported may be explained by increased synthesis of G6PD molecules per unit of hemoglobin or to reduced inactivation in the RBC hemolysate.

  6. Fundamental studies on the insulin receptor in rabbit erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Shinomiya, Y; Kagawa, S; Konishi, Y; Morimoto, H; Tsumura, Y [Hyogo Medical Coll. (Japan)

    1975-09-01

    The authors studied the binding of insulin to rabbit erythrocytes as a mode case in the hope of characterizing the physiologic role of the binding of insulin to receptor in both normal adults and patients. Specific binding sites for insulin were detected in rabbit erythrocytes. The characteristics of the binding were similar to those observed in other target tissues. The specific binding of /sup 125/I-labeled insulin was competitively inhibited by a small amount of unlabeled insulin and was completely inhibited by 1,000 ng/ml of unlabeled insulin. Glucagon, however, had no effect on the insulin binding to fat cells or liver membranes nor had it any effect on the binding of insulin to rabbit erythrocytes. Scatchard analysis of this binding reaction indicated two different binding sites with Ksub(aff)=3.2 x 10/sup 8//M, Ksub(diss)=3.1 x 10/sup -9/M; Ksub(aff)=1.4 x 10/sup 8//M, Ksub(diss)=7.1 x 10/sup -9/M respectively, and the binding capacities of each site were estimated at 0.011 ng/4 x 10/sup 8/ cells and 0.138 ng/4 x 10/sup 8/ cells. The binding of /sup 125/I-insulin to rabbit erythrocytes was a saturable function of the insulin concentration and was a linear function of cell concentration. The pH optimum for the reaction was 7.4 at 0/sup 0/C, the amount of insulin binding increased continuously under the reaction and this binding reaction reached a steady state after 10 to 15hr. On the other hand, the specific binding of insulin at higher temperatures showed maximal amounts after 20 to 30 min. and subsequently fell off at later time points.

  7. Human erythrocytes inhibit complement-mediated solubilization of immune complexes by human serum

    International Nuclear Information System (INIS)

    Dorval, B.L.

    1987-01-01

    The aim of this study was to develop an autologus human system to evaluate the effects of human erythrocytes on solubilization of immune complex precipitates (IC) by human serum. Incubation of IC with fresh human serum or guinea pig serum resulted in solubilization of IC. When packed erythrocytes were added to human serum or guinea pig serum binding of IC to the erythrocyte occurred and IC solubilization was inhibited significantly (p <.025). Sheep erythrocytes did not bind IC or inhibit IC solubilization. To evaluate the role of human erythrocyte complement receptor (CR1) on these findings, human erythrocytes were treated with trypsin or anti-CR1 antibodies. Both treatments abrogated IC binding to human erythrocytes but did not affect the ability of the human erythrocyte to inhibit IC solubilization. Radioimmunoassay was used to measure C3, C4 and C5 activation in human serum after incubation with IC, human erythrocytes, human erythrocytes plus IC, whole blood or in whole blood plus IC

  8. Bilayer/cytoskeleton interactions in lipid-symmetric erythrocytes assessed by a photoactivable phospholipid analogue

    International Nuclear Information System (INIS)

    Pradhan, D.; Schlegel, R.A.; Williamson, P.

    1991-01-01

    Two mechanisms have been proposed for maintenance of transbilayer phospholipid asymmetry in the erythrocyte plasma membrane, one involving specific interactions between the aminophospholipids of the inner leaflet of the bilayer and the cytoskeleton, particularly spectrin, and the other involving the aminophospholipid translocase. If the former mechanism is correct, then erythrocytes which have lost their asymmetric distribution of phospholipids should display altered bilayer/cytoskeleton interactions. To test this possibility, normal erythrocytes, erythrocytes from patients with chronic myelogenous leukemia or sickle disease, and lipid-symmetric and -asymmetric erythrocyte ghosts were labeled with the radioactive photoactivable analogue of phosphatidylethanolamine, 2-(2-azido-4-nitrobenzoyl)-1-acyl-sn-glycero-3-phospho[ 14 C] ethanolamine ([ 14 C]AzPE), previously shown to label cytoskeletal proteins from the bilayer. The labeling pattern of cytoskeletal proteins in pathologic erythrocytes and lipid-asymmetric erythrocyte ghosts was indistinguishable from normal erythrocytes, indicating that the probe detects no differences in bilayer/cytoskeleton interactions in these cells. In contrast, in lipid-symmetric erythrocyte ghosts, labeling of bands 4.1 and 4.2 and actin, and to a lesser extent ankyrin, by [ 14 C]AzPE was considerably reduced. Significantly, however, labeling of spectrin was unaltered in the lipid-symmetric cells. These results do not support a model in which spectrin is involved in the maintenance of an asymmetric distribution of phospholipids in erythrocytes

  9. Transverse water relaxation in whole blood and erythrocytes at 3T, 7T, 9.4T, 11.7T and 16.4T; determination of intracellular hemoglobin and extracellular albumin relaxivities.

    Science.gov (United States)

    Grgac, Ksenija; Li, Wenbo; Huang, Alan; Qin, Qin; van Zijl, Peter C M

    2017-05-01

    Blood is a physiological substance with multiple water compartments, which contain water-binding proteins such as hemoglobin in erythrocytes and albumin in plasma. Knowing the water transverse (R 2 ) relaxation rates from these different blood compartments is a prerequisite for quantifying the blood oxygenation level-dependent (BOLD) effect. Here, we report the Carr-Purcell-Meiboom-Gill (CPMG) based transverse (R 2CPMG ) relaxation rates of water in bovine blood samples circulated in a perfusion system at physiological temperature in order to mimic blood perfusion in humans. R 2CPMG values of blood plasma, lysed packed erythrocytes, lysed plasma/erythrocyte mixtures, and whole blood at 3 T, 7 T, 9.4 T, 11.7 T and 16.4 T were measured as a function of hematocrit or hemoglobin concentration, oxygenation, and CPMG inter-echo spacing (τ cp ). R 2CPMG in lysed cells showed a small τ cp dependence, attributed to the water exchange rate between free and hemoglobin-bound water to be much faster than τ cp . This was contrary to the tangential dependence in whole blood, where a much slower exchange between cells and blood plasma applies. Whole blood data were fitted as a function of τ cp using a general tangential correlation time model applicable for exchange as well as diffusion contributions to R 2CPMG , and the intercept R 20blood at infinitely short τ cp was determined. The R 20blood values at different hematocrit and the R 2CPMG values of lysed erythrocyte/plasma mixtures at different hemoglobin concentration were used to determine the relaxivity of hemoglobin inside the erythrocyte (r 2Hb ) and albumin (r 2Alb ) in plasma. The r 2Hb values obtained from lysed erythrocytes and whole blood were comparable at full oxygenation. However, while r 2Hb determined from lysed cells showed a linear dependence on oxygenation, this dependence became quadratic in whole blood. This possibly suggests an additional relaxation effect inside intact cells, perhaps due to hemoglobin

  10. Oxygen safety

    Science.gov (United States)

    ... sure you have working smoke detectors and a working fire extinguisher in your home. If you move around the house with your oxygen, you may need more than one fire extinguisher in different locations. Smoking can be very dangerous. No one should smoke ...

  11. Transport of 3-bromopyruvate across the human erythrocyte membrane.

    Science.gov (United States)

    Sadowska-Bartosz, Izabela; Soszyński, Mirosław; Ułaszewski, Stanisław; Ko, Young; Bartosz, Grzegorz

    2014-06-01

    3-Bromopyruvic acid (3-BP) is a promising anticancer compound because it is a strong inhibitor of glycolytic enzymes, especially glyceraldehyde 3-phosphate dehydrogenase. The Warburg effect means that malignant cells are much more dependent on glycolysis than normal cells. Potential complications of anticancer therapy with 3-BP are side effects due to its interaction with normal cells, especially erythrocytes. Transport into cells is critical for 3-BP to have intracellular effects. The aim of our study was the kinetic characterization of 3-BP transport into human erythrocytes. 3-BP uptake by erythrocytes was linear within the first 3 min and pH-dependent. The transport rate decreased with increasing pH in the range of 6.0-8.0. The Km and Vm values for 3-BP transport were 0.89 mM and 0.94 mmol/(l cells x min), respectively. The transport was inhibited competitively by pyruvate and significantly inhibited by DIDS, SITS, and 1-cyano-4-hydroxycinnamic acid. Flavonoids also inhibited 3-BP transport: the most potent inhibition was found for luteolin and quercetin.

  12. Proton NMR studies of creatine in human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kuchel, P W; Chapman, B E [Sydney Univ. (Australia). Dept. of Biochemistry

    1983-09-01

    Proton spin-echo nuclear magnetic resonance spectroscopy was used to measure the relative levels of some metabolites in intact human erythrocytes that had been fractionated by density gradient centrifugation. Age dependent changes in the concentrations of free glycine, choline and ergothioneine were seen for the first time, while glutathione was essentially invariant. In addition, there was a 10-fold decrease in creatine levels from the youngest to oldest cells. This confirms earlier reports and provides a simple explanation for the variable creatine resonance intensities seen in spectra obtained from different erythrocyte samples prepared from the same donor. The different chemical shifts of the methylene resonances of creatine and creatine phosphate was demonstrated and hence confirmed that the bulk of the creatine in intact erythrocytes is not phosphorylated. The chemical shift difference enabled the monitoring of the creatine phosphokinase catalysed reaction in lysates to which the rabbit muscle enzyme had been added. This experiment indicated that the enzyme is not significantly inhibited by factors in the lysates, and introduced a new means of assaying the in situ activity of the enzyme.

  13. Drug-loaded erythrocytes: on the road toward marketing approval

    Directory of Open Access Journals (Sweden)

    Bourgeaux V

    2016-02-01

    Full Text Available Vanessa Bourgeaux,1 José M Lanao,2 Bridget E Bax,3 Yann Godfrin11ERYTECH Pharma, Lyon, France; 2Department of Pharmacy and Pharmaceutical Technology, University of Salamanca, Salamanca, Spain; 3Cardiovascular and Cell Sciences Research Institute, St George’s University of London, London, UKAbstract: Erythrocyte drug encapsulation is one of the most promising therapeutic alternative approaches for the administration of toxic or rapidly cleared drugs. Drug-loaded erythrocytes can operate through one of the three main mechanisms of action: extension of circulation half-life (bioreactor, slow drug release, or specific organ targeting. Although the clinical development of erythrocyte carriers is confronted with regulatory and development process challenges, industrial development is expanding. The manufacture of this type of product can be either centralized or bedside based, and different procedures are employed for the encapsulation of therapeutic agents. The major challenges for successful industrialization include production scalability, process validation, and quality control of the released therapeutic agents. Advantages and drawbacks of the different manufacturing processes as well as success key points of clinical development are discussed. Several entrapment technologies based on osmotic methods have been industrialized. Companies have already achieved many of the critical clinical stages, thus providing the opportunity in the future to cover a wide range of diseases for which effective therapies are not currently available.Keywords: red blood cell, encapsulation method, drug carrier, industrial development, clinical use

  14. Proton NMR studies of creatine in human erythrocytes

    International Nuclear Information System (INIS)

    Kuchel, P.W.; Chapman, B.E.

    1983-01-01

    Proton spin-echo nuclear magnetic resonance spectroscopy was used to measure the relative levels of some metabolites in intact human erythrocytes that had been fractionated by density gradient centrifugation. Age dependent changes in the concentrations of free glycine, choline and ergothioneine were seen for the first time, while glutathione was essentially invariant. In addition, there was a 10-fold decrease in creatine levels from the youngest to oldest cells. This confirms earlier reports and provides a simple explanation for the variable creatine resonance intensities seen in spectra obtained from different erythrocyte samples prepared from the same donor. The different chemical shifts of the methylene resonances of creatine and creatine phosphate was demonstrated and hence confirmed that the bulk of the creatine in intact erythrocytes is not phosphorylated. The chemical shift difference enabled the monitoring of the creatine phosphokinase catalysed reaction in lysates to which the rabbit muscle enzyme had been added. This experiment indicated that the enzyme is not significantly inhibited by factors in the lysates, and introduced a new means of assaying the in situ activity of the enzyme. (author)

  15. Age related changes in erythrocyte A and B antigen strength

    Energy Technology Data Exchange (ETDEWEB)

    Hollingsworth, J W; Hamilton, H B; Ishii, Goro

    1961-11-01

    The strength of A and B antigens of the erythrocyte, as indicated by agglutinability with dilutions of specific antibody, has been investigated in a group of subjects in Hiroshima. Antigen strength was found to rise to maximal levels at age 25 to 29, and decline with advancing years. Degree of irradiation from the Hiroshima atomic bomb in 1945 did not appear in the limited sample to affect this age-dependent structural property of erythrocytes. Antigen strength of females was somewhat less than that of males for those individuals from 20 to 40 years of age. When compared with group A or B subjects, individuals of group AB demonstrated full strength of both A and B antigens. Since Rh antigenicity also has been reported to change with age, it seems probable that multiple changes in the erythrocyte membrane occur with age. Further investigation into the nature of these changes may be fruitful to an understanding of aging processes at the cellular level. 13 references, 1 figure, 6 tables.

  16. Heme Sensor Proteins*

    Science.gov (United States)

    Girvan, Hazel M.; Munro, Andrew W.

    2013-01-01

    Heme is a prosthetic group best known for roles in oxygen transport, oxidative catalysis, and respiratory electron transport. Recent years have seen the roles of heme extended to sensors of gases such as O2 and NO and cell redox state, and as mediators of cellular responses to changes in intracellular levels of these gases. The importance of heme is further evident from identification of proteins that bind heme reversibly, using it as a signal, e.g. to regulate gene expression in circadian rhythm pathways and control heme synthesis itself. In this minireview, we explore the current knowledge of the diverse roles of heme sensor proteins. PMID:23539616

  17. Oxygen therapy - infants

    Science.gov (United States)

    ... breathe increased amounts of oxygen to get normal levels of oxygen in their blood. Oxygen therapy provides babies with the extra oxygen. Information Oxygen is a gas that the cells in your body need to work properly. The ...

  18. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under

  19. Chemical sensors for nuclear industry

    International Nuclear Information System (INIS)

    Gnanasekaran, K.I.

    2012-01-01

    Development of chemical sensors for detection of gases at trace levels for applications in nuclear industry will be highlighted. The sensors have to be highly sensitive, reliable and rugged with long term stability to operate in harsh industrial environment. Semiconductor and solid electrolyte based electrochemical sensors satisfy the requirements. Physico-chemical aspects underlying the development of H 2 sensors in sodium and in cover gas circuit of the Fast breeder reactors for its smooth functioning, NH 3 and H 2 S sensors for use in Heavy water production industries and NO x sensors for spent fuel reprocessing plants will be presented. Development of oxygen sensors to monitor the oxygen level in the reactor containments and sodium sensors for detection of sodium leakages will also be discussed. The talk will focus the general aspects of identification of the sensing material for the respective analyte species, development of suitable chemical route for preparing them as fine powders, the need for configuring them in thick film or thin film geometries and their performance. Pulsed laser deposition method, an elegant technique to prepare the high quality thin films of multicomponent oxides is demonstrated for preparation of nanostructured thin films of complex oxides and its use in tailoring the morphology of the complex sensing material in the desired form by optimizing the in-situ growth conditions. (author)

  20. Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    Science.gov (United States)

    Hunter, Gary W.

    2005-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors; 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity; 3) The development of high temperature semiconductors, especially silicon carbide. This presentation discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  1. A Lectin-Like Receptor is Involved in Invasion of Erythrocytes by Plasmodium falciparum

    Science.gov (United States)

    Jungery, M.; Pasvol, G.; Newbold, C. I.; Weatherall, D. J.

    1983-02-01

    Glycophorin both in solution and inserted into liposomes blocks invasion of erythrocytes by the malaria parasite Plasmodium falciparum. Furthermore, one sugar, N-acetyl-D-glucosamine (GlcNAc), completely blocks invasion of the erythrocyte by this parasite. GlcNAc coupled to bovine serum albumin to prevent the sugar entering infected erythrocytes was at least 100,000 times more effective than GlcNAc alone. Bovine serum albumin coupled to lactose or bovine serum albumin alone had no effect on invasion. These results suggest that the binding of P. falciparum to erythrocytes is lectin-like and is determined by carbohydrates on glycophorin.

  2. Stimulation of ceramide formation and suicidal erythrocyte death by vitamin K(3) (menadione).

    Science.gov (United States)

    Qadri, Syed M; Eberhard, Matthias; Mahmud, Hasan; Föller, Michael; Lang, Florian

    2009-11-25

    Vitamin K(3) is an essential micronutrient required for the activation of coagulation factors and thus hemostasis. Administration of vitamin K(3) analogues may cause anemia, which at least in theory could be due to stimulation of suicidal erythrocyte death or eryptosis characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane leading to exposure of phosphatidylserine at the erythrocyte surface. Eryptosis is triggered by an increase in the cytosolic Ca(2+) activity, by ceramide and by energy depletion (decrease of cytosolic ATP). The present experiments explored, whether vitamin K(3) may influence eryptosis. Hemolysis was estimated from the supernatant hemoglobin concentration, phosphatidylserine-exposing erythrocytes from annexin V-binding in fluorescence-activated cell sorter (FACS) analysis, erythrocyte volume from forward scatter in FACS analysis, ceramide formation from binding of fluorescent antibodies, and erythrocyte ATP content from a luciferin-luciferase assay. As a result, vitamin K(3) (> or =1microM) caused lysis of an only small fraction of erythrocytes, but significantly increased ceramide formation, significantly increased the percentage of annexin V-binding erythrocytes, significantly decreased forward scatter and, at higher concentrations, significantly decreased the cellular ATP content. In conclusion, vitamin K(3) stimulates suicidal erythrocyte death, an effect at least partially due to ceramide formation and ATP depletion.

  3. Effect of dietary zinc deficiency on the endogenous phosphorylation and dephosphorylation of rat erythrocyte membrane

    International Nuclear Information System (INIS)

    Paterson, P.G.; Allen, O.B.; Bettger, W.J.

    1987-01-01

    The effect of dietary zinc deficiency on patterns of phosphorylation and dephosphorylation of rat erythrocyte membrane proteins and erythrocyte filterability was examined. Weanling male Wistar rats were fed an egg white-based diet containing less than 1.1 mg zinc/kg diet ad libitum for 3 wk. Control rats were either pair-fed or ad libitum-fed the basal diet supplemented with 100 mg zinc/kg diet. Net phosphorylation and dephosphorylation of erythrocyte membrane proteins were carried out by an in vitro assay utilizing [gamma- 32 P]ATP. The membrane proteins were subsequently separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the 32 P content of gel slices was counted by Cerenkov counting. Erythrocyte filterability was measured as the filtration time of suspensions of erythrocytes, both untreated and preincubated with diamide, under constant pressure. Erythrocyte ghosts from zinc-deficient rats demonstrated greater dephosphorylation of protein bands R1 plus R2 and R7 than pair-fed rats and greater net phosphorylation of band R2.2 than pair-fed or ad libitum-fed control rats (P less than 0.05). Erythrocytes from ad libitum-fed control rats showed significantly longer filtration times than those from zinc-deficient or pair-fed control rats. In conclusion, dietary zinc deficiency alters in vitro patterns of erythrocyte membrane protein phosphorylation and dephosphorylation, whereas the depression in food intake associated with the zinc deficiency increases erythrocyte filterability. 71 references

  4. Morphometric analysis of erythrocytes from patients with thalassemia using tomographic diffractive microscopy

    Science.gov (United States)

    Lin, Yang-Hsien; Huang, Shin-Shyang; Wu, Shang-Ju; Sung, Kung-Bin

    2017-11-01

    Complete blood count is the most common test to detect anemia, but it is unable to obtain the abnormal shape of erythrocytes, which highly correlates with the hematologic function. Tomographic diffractive microscopy (TDM) is an emerging technique capable of quantifying three-dimensional (3-D) refractive index (RI) distributions of erythrocytes without labeling. TDM was used to characterize optical and morphological properties of 172 erythrocytes from healthy volunteers and 419 erythrocytes from thalassemic patients. To efficiently extract and analyze the properties of erythrocytes, we developed an adaptive region-growing method for automatically delineating erythrocytes from 3-D RI maps. The thalassemic erythrocytes not only contained lower hemoglobin content but also showed doughnut shape and significantly lower volume, surface area, effective radius, and average thickness. A multi-indices prediction model achieved perfect accuracy of diagnosing thalassemia using four features, including the optical volume, surface-area-to-volume ratio, sphericity index, and surface area. The results demonstrate the ability of TDM to provide quantitative, hematologic measurements and to assess morphological features of erythrocytes to distinguish healthy and thalassemic erythrocytes.

  5. Effect of 2,3-diphosphoglycerate on oxygen affinity of blood in sickle cell anemia

    Science.gov (United States)

    Charache, Samuel; Grisolia, Santiago; Fiedler, Adam J.; Hellegers, Andre E.

    1970-01-01

    Blood of patients with sickle cell anemia (SS) exhibits decreased affinity for oxygen, although the oxygen affinity of hemoglobin S is the same as that of hemoglobin A. SS red cells contain more 2,3-diphosphoglycerate (DPG) than normal erythrocytes. The oxygen affinity of hemolyzed red cells is decreased by added DPG, and hemolysates prepared from SS red cells do not differ from normal hemolysates in this regard. Reduction of oxygen affinity to the levels found in intact SS red cells required DPG concentrations in excess of those found in most SS patients. The same was true of oxygen affinity of patients with pyruvate kinase deficiency. Other organic phosphates, as well as inorganic ions, are known to alter the oxygen affinity of dilute solutions of hemoglobin. These substances, the state of aggregation of hemoglobin molecules, and cytoarchitectural factors probably play roles in determining oxygen affinity of both normal and SS red cells. PMID:5443181

  6. Interaction of erythrocytes and hexavalent uranium compounds -an autoanalytical study

    International Nuclear Information System (INIS)

    Stuart, W.I.; Shying, M.E.

    1980-05-01

    An automated analytical system was devised to measure the kinetics of hemolysis by uranyl compounds. Accurate plots of percentage hemolysis v. time were obtained; these, together with the corresponding differential curves, show that hemolysis of plasma-free erythrocytes is a two-stage process. The first stage of hemolysis is particularly affected by pH and anion content of uranyl solutions, and also by incubation of cell suspensions at 37 deg. before mixing with lysing solution. Complementary studies involving Coulter counting and microscopic observation established the general pattern of hemolysis and showed that cell agglutination is a prominent feature of the interaction of cells with uranyl solutions

  7. Human erythrocyte electrofusion kinetics monitored by aqueous contents mixing.

    OpenAIRE

    Stenger, D A; Hui, S W

    1988-01-01

    The kinetics of electrically induced fusion of human erythrocyte ghosts were monitored by the Tb/DPA and ANTS/DPX fluorescence fusion assays. Ghosts were aligned by dielectrophoresis using a 3-MHz 350-V/cm alternating field and were fused by single 15- or 50-microseconds electric field pulses of amplitude 2.5-5.0 kV/cm. Fusion was detected immediately after the pulse. The peak fluorescence change due to fusion was always obtained within 7 s of pulse application, and was highest for a 5.0 kV/c...

  8. Air to fuel ratio sensor for internal combustion engine control system; Nainen kikan no nensho seigyoyo kunen hi sensor

    Energy Technology Data Exchange (ETDEWEB)

    Tsuzuki, M.; Kawai, T.; Yamada, T.; Nishio [NGK Spark Plug Co. Ltd., Aichi (Japan)

    1998-06-01

    Air to fuel ratio sensor is used for emission control system of three-way catalyst, and constitutes the important functional part of combustion control system. For further precise combustion control application, universal air to fuel ratio heated exhaust gas oxygen sensor (UEGO sensor) has been developed. This paper introduces heater control system for constant element temperature of UEGO sensor. By the heater wattage feedback control of sensing cell impedance, the change of sensor element temperature is decreased. 9 refs., 13 figs.

  9. Decreased erythrocyte superoxide dismutase in elderly men with early nuclear cataract

    Directory of Open Access Journals (Sweden)

    Rose Rose

    2015-12-01

    Full Text Available BACKGROUND Imbalance between oxidative processes and antioxidant defenses has been considered to play a role in cataractogenesis, particularly in diabetes patients. Superoxide dismutase (SOD is an important precursor for oxidative stress in the human lens, and its activity is mainly dependent on the copper and zinc levels in the body. The aim of this study was to compare erythrocyte SOD, erythrocyte zinc and total serum testosterone levels in male patients with early senile nuclear cataract and evaluate the correlations between the parameters in all subjects. METHODS A community-based study of cross-sectional design was conducted at Cilandak District Primary Health Center where 52 adult and 17 elderly men with early senile nuclear cataract were chosen as the study subjects. Erythrocyte SOD, erythrocyte zinc, serum testosterone, and fasting blood glucose (FBG levels were measured in all subjects. Nuclear cataract stage was assessed with the Pentacam® instrument (Oculus, Germany. Independent Student t test and Pearson’s correlation were used to analyze the results. RESULTS Erythrocyte SOD level was significantly decreased in elderly men compared to adult men (p=0.014. Erythrocyte zinc, serum testosterone and FBG did not differ significantly in adult and elderly males (at p=0.304; p=0.145;and p=0.376, respectively. Erythrocyte SOD activity was significantly associated with erythrocyte zinc level (r=0.486; p=0.048. CONCLUSIONS Lower erythrocyte SOD activity was found in elderly males than in adult males with early nuclear cataract. There was a relationship between erythrocyte SOD and erythrocyte zinc level in elderly males with early nuclear cataract.

  10. Decreased erythrocyte superoxide dismutase in elderly men with early nuclear cataract

    Directory of Open Access Journals (Sweden)

    Rose

    2014-04-01

    Full Text Available BACKGROUND Imbalance between oxidative processes and antioxidant defenses has been considered to play a role in cataractogenesis, particularly in diabetes patients. Superoxide dismutase (SOD is an important precursor for oxidative stress in the human lens, and its activity is mainly dependent on the copper and zinc levels in the body. The aim of this study was to compare erythrocyte SOD, erythrocyte zinc and total serum testosterone levels in male patients with early senile nuclear cataract and evaluate the correlations between the parameters in all subjects. METHODS A community-based study of cross-sectional design was conducted at Cilandak District Primary Health Center where 52 adult and 17 elderly men with early senile nuclear cataract were chosen as the study subjects. Erythrocyte SOD, erythrocyte zinc, serum testosterone, and fasting blood glucose (FBG levels were measured in all subjects. Nuclear cataract stage was assessed with the Pentacam® instrument (Oculus, Germany. Independent Student t test and Pearson’s correlation were used to analyze the results. RESULTS Erythrocyte SOD level was significantly decreased in elderly men compared to adult men (p=0.014. Erythrocyte zinc, serum testosterone and FBG did not differ significantly in adult and elderly males (at p=0.304; p=0.145;and p=0.376, respectively. Erythrocyte SOD activity was significantly associated with erythrocyte zinc level (r=0.486; p=0.048. CONCLUSIONS Lower erythrocyte SOD activity was found in elderly males than in adult males with early nuclear cataract. There was a relationship between erythrocyte SOD and erythrocyte zinc level in elderly males with early nuclear cataract.

  11. Erythrocyte-like hollow carbon capsules and their application in proton exchange membrane fuel cells.

    Science.gov (United States)

    Kim, Jung Ho; Yu, Jong-Sung

    2010-12-14

    Hierarchical nanostructured erythrocyte-like hollow carbon (EHC) with a hollow hemispherical macroporous core of ca. 230 nm in diameter and 30-40 nm thick mesoporous shell was synthesized and explored as a cathode catalyst support in a proton exchange membrane fuel cell (PEMFC). The morphology control of EHC was successfully achieved using solid core/mesoporous shell (SCMS) silica template and different styrene/furfuryl alcohol mixture compositions by a nanocasting method. The EHC-supported Pt (20 wt%) cathodes prepared have demonstrated markedly enhanced catalytic activity towards oxygen reduction reactions (ORRs) and greatly improved PEMFC polarization performance compared to carbon black Vulcan XC-72 (VC)-supported ones, probably due to the superb structural characteristics of the EHC such as uniform size, well-developed porosity, large specific surface area and pore volume. In particular, Pt/EHC cathodes exhibited ca. 30-60% higher ORR activity than a commercial Johnson Matthey Pt catalyst at a low catalyst loading of 0.2 mg Pt cm(-2).

  12. Posttransfusional changes of 2,3-diphosphoglycerate and nucleotides in CPD-SAGM-preserved erythrocytes.

    Science.gov (United States)

    Matthes, G; Strunk, S; Siems, W; Grune, T

    1993-06-01

    Posttransfusional changes of preserved red blood cells can influence the oxygen equilibrium curve which is mainly affected by the concentration of erythrocyte 2,3-diphosphoglycerate (DPG). The regeneration kinetics of DPG and nucleotides (ATP, ADP, AMP, GTP, GDP) was determined over a period of 0-48 h in surgically treated patients following transfusion of DPG-depleted packed red cells stored for 14 days in CPD-SAGM. 3 h after transfusion the DPG levels raised up to 40% of the patients' prior DPG concentrations. Complete regeneration of the DPG concentrations occurred 36-48 h after transfusion. Changes in the nucleotide pattern indicate, after a temporary decrease of ATP and GTP levels (after 10-30 min) and an activation phase (after 3-12 h), the full regeneration of these parameters 24-48 h after transfusion. The regeneration kinetics of DPG should be taken into consideration for transfusions with blood units stored for more than 14 days, especially in patients with reduced compensatory mechanisms (coronary and cerebral scleroses, pacemaker, etc.) and large transfusion volumes.

  13. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built

  14. Anemia in chronic renal failure. Ferrokinetic, erythrocytes-survival time and enzymes of erythrocytes on chronic dialysed patients

    Energy Technology Data Exchange (ETDEWEB)

    Junkers, K; Jontofson, R; Meuret, G; Blume, K G; Heinze, V [Freie Univ. Berlin (F.R. Germany). Nuklearmedizinische Abt.; Freiburg Univ. (F.R. Germany). Nuklearmedizinische Abt.; Freiburg Univ. (F.R. Germany). Medizinische Poliklinik)

    1975-12-01

    Radio-iron utilization was nearly normal in these patients, only bilateral nephrectomized patients showed a reduced radio-iron utilization. Red blood half-life span was shortened in all patients, well corresponding to the degree of anemia. Parameters of erythropoesis like plasma iron clearance, bone marrow transit time, erythron iron turnover, non-erythron iron turnover and hemolysis iron turnover failed to quantitate disorders of red blood cell regeneration in these patients. No defect in red blood cell enzyme activity could be demonstrated. Enzymes of glycolysis were increased corresponding to the reduced erythrocyte half-life span.

  15. Aquatic respiration rate measurements at low oxygen concentrations.

    Directory of Open Access Journals (Sweden)

    Moritz Holtappels

    Full Text Available Despite its huge ecological importance, microbial oxygen respiration in pelagic waters is little studied, primarily due to methodological difficulties. Respiration measurements are challenging because of the required high resolution of oxygen concentration measurements. Recent improvements in oxygen sensing techniques bear great potential to overcome these limitations. Here we compare 3 different methods to measure oxygen consumption rates at low oxygen concentrations, utilizing amperometric Clark type sensors (STOX, optical sensors (optodes, and mass spectrometry in combination with (18-18O2 labeling. Oxygen concentrations and consumption rates agreed well between the different methods when applied in the same experimental setting. Oxygen consumption rates between 30 and 400 nmol L(-1 h(-1 were measured with high precision and relative standard errors of less than 3%. Rate detection limits in the range of 1 nmol L(-1 h(-1 were suitable for rate determinations in open ocean water and were lowest at the lowest applied O2 concentration.

  16. Altered erythrocyte Na-K pump in anorectic patients

    International Nuclear Information System (INIS)

    Pasquali, R.; Strocchi, E.; Malini, P.; Casimirri, F.; Ambrosioni, E.; Melchionda, N.; Labo, G.

    1985-01-01

    The status of the erythrocyte sodium pump was evaluated in a group of patients suffering from anorexia nervosa and a group of healthy female control subjects. Anorectic patients showed significantly higher mean values of digoxin-binding sites/cell (ie, the number of Na-K-ATPase units) with respect to control subjects while no differences were found in the specific 86 Rb uptake (which reflects the Na-K-ATPase activity) between the two groups. A significant correlation was found between relative weight and the number of Na-K-ATPase pump units (r = -0.66; P less than 0.0001). Anorectic patients showed lower serum T3 concentrations (71.3 +/- 53 ng/dL) with respect to control subjects (100.8 +/- 4.7 ng/dL; P less than 0.0005) and a significant negative correlation between T3 levels and the number of pump units (r = -0.52; P less than 0.003) was found. This study therefore shows that the erythrocyte Na-K pump may be altered in several anorectic patients. The authors suggest that this feature could be interrelated with the degree of underweight and/or malnutrition

  17. The knocked-out erythrocyte sedimentation rate: periodontal abscess.

    Science.gov (United States)

    Sevinc, Alper; Bayindir, Yasar; But, Ayse

    2008-01-01

    The erythrocyte sedimentation rate (ESR) is a common but nonspecific test that is often used as an indicator of active disease. Infection of dental origin may be responsible for a number of cases in unresolved elevated ESR and fever etiology. Dental sepsis is the one of the potential causes of persistent fever that can escape detection. An 18-year-old female patient was admitted to the emergency room with complaints of headache, fever, nausea, and vomiting for the past four days. Erythrocyte sedimentation rate was 110 mm/h. She was started empirically on antibiotic treatment as no etiology was found. Four days later, while searching for the etiology of the fever, the patient experienced an acute pain in association with localizing symptoms in two decayed teeth. Oral examination revealed abscess formation in both teeth. Teeth were extracted and ESR was decreased to 95 mm/h on the day of the second extraction and to 60, 35, and 10 mm/h taken weekly. During the follow-up, she was in good health with no fever seen 3 months after treatment and her ESR was 15 mm/h. Dental infection should be considered as an unusual but very treatable cause of pyrexia of unknown origin.

  18. Carbohydrate metabolism in erythrocytes of copper deficient rats.

    Science.gov (United States)

    Brooks, S P J; Cockell, K A; Dawson, B A; Ratnayake, W M N; Lampi, B J; Belonje, B; Black, D B; Plouffe, L J

    2003-11-01

    Dietary copper deficiency is known to adversely affect the circulatory system of fructose-fed rats. Part of the problem may lie in the effect of copper deficiency on intermediary metabolism. To test this, weanling male Long-Evans rats were fed for 4 or 8 weeks on sucrose-based diets containing low or adequate copper content. Copper deficient rats had significantly lower plasma and tissue copper as well as lower plasma copper, zinc-superoxide dismutase activity. Copper deficient rats also had a significantly higher heart:body weight ratio when compared to pair-fed controls. Direct measurement of glycolysis and pentose phosphate pathway flux in erythrocytes using (13)C NMR showed no differences in carbon flux from glucose or fructose to pyruvate but a significantly higher flux through the lactate dehydrogenase locus in copper deficient rats (approximately 1.3 times, average of glucose and glucose + fructose measurements). Copper-deficient animals had significantly higher erythrocyte concentrations of glucose, fructose, glyceraldehyde 3-phosphate and NAD(+). Liver metabolite levels were also affected by copper deficiency being elevated in glycogen and fructose 1-phosphate content. The results show small changes in carbohydrate metabolism of copper deficient rats.

  19. Physicochemical characterization of artificial nanoerythrosomes derived from erythrocyte ghost membranes.

    Science.gov (United States)

    Deák, Róbert; Mihály, Judith; Szigyártó, Imola Cs; Wacha, András; Lelkes, Gábor; Bóta, Attila

    2015-11-01

    Colloidal stabile nanoerythrosomes with 200 nm average diameter were formed from hemoglobin-free erythrocyte ghost membrane via sonication and membrane extrusion. The incorporation of extra lipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC), added to the sonicated ghosts, caused significant changes in the thermotropic character of the original membranes. As a result of the increased DPPC ratio the chain melting of the hydrated DPPC system and the characteristic small angle X-ray scattering (SAXS) of the lipid bilayers appeared. Significant morphological changes were followed by transmission electron microscopy combined with freeze fracture method (FF-TEM). After the ultrasonic treatment the large entities of erythrocyte ghosts transformed into nearly spherical nanoerythrosomes with diameters between 100 and 300 nm and at the same time a great number of 10-30 nm large membrane proteins or protein clusters were dispersed in the aqueous medium. The infrared spectroscopy (FT-IR) pointed out, that the sonication did not cause changes in the secondary structures of the membrane proteins under our preparation conditions. About fivefold of extra lipid--compared to the lipid content of the original membrane--caused homogeneous dispersion of nanoerythrosomes however the shape of the vesicles was not uniform. After the addition of about tenfold of DPPC, monoform and monodisperse nanoerythrosomes became typical. The outer surfaces of these roughly spherical objects were frequently polygonal, consisting of a net of pentagons and hexagons. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Hepatic and erythrocytic glutathione peroxidase activity in liver diseases.

    Science.gov (United States)

    Cordero, R; Ortiz, A; Hernández, R; López, V; Gómez, M M; Mena, P

    1996-09-01

    Hepatic and erythrocytic glutathione peroxidase activity, together with malondialdehyde levels, were determined as indicators of peroxidation in 83 patients from whom liver biopsies had been taken for diagnostic purposes. On histological study, the patients were classified into groups as minimal changes (including normal liver), steatosis, alcoholic hepatitis, hepatic cirrhosis, light to moderately active chronic hepatitis, and severe chronic active hepatitis. The glutathione peroxidase activity in erythrocytes showed no significant changes in any liver disease group. In the hepatic study, an increased activity was observed in steatosis with respect to the minimal changes group, this increased activity induced by the toxic agent in the initial stages of the alcoholic hepatic disease declining as the hepatic damage progressed. There was a negative correlation between the levels of hepatic malondialdehyde and hepatic glutathione peroxidase in subjects with minimal changes. This suggested the existence of an oxidative equilibrium in this group. This equilibrium is broken in the liver disease groups as was manifest in a positive correlation between malondialdehyde and glutathione peroxidase activity.

  1. Plasmodium falciparum erythrocyte invasion: combining function with immune evasion.

    Directory of Open Access Journals (Sweden)

    Gavin J Wright

    2014-03-01

    Full Text Available All the symptoms and pathology of malaria are caused by the intraerythrocytic stages of the Plasmodium parasite life cycle. Because Plasmodium parasites cannot replicate outside a host cell, their ability to recognize and invade erythrocytes is an essential step for both parasite survival and malaria pathogenesis. This makes invasion a conceptually attractive vaccine target, especially because it is one of the few stages when the parasite is directly exposed to the host humoral immune system. This apparent vulnerability, however, has been countered by the parasite, which has evolved sophisticated molecular mechanisms to evade the host immune response so that parasites asymptomatically replicate within immune individuals. These mechanisms include the expansion of parasite invasion ligands, resulting in multiple and apparently redundant invasion "pathways", highly polymorphic parasite surface proteins that are immunologically distinct, and parasite proteins which are poorly immunogenic. These formidable defences have so far thwarted attempts to develop an effective blood-stage vaccine, leading many to question whether there really is an exploitable chink in the parasite's immune evasion defences. Here, we review recent advances in the molecular understanding of the P. falciparum erythrocyte invasion field, discuss some of the challenges that have so far prevented the development of blood-stage vaccines, and conclude that the parasite invasion ligand RH5 represents an essential pinch point that might be vulnerable to vaccination.

  2. Altered erythrocyte Na-K pump in anorectic patients

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, R.; Strocchi, E.; Malini, P.; Casimirri, F.; Ambrosioni, E.; Melchionda, N.; Labo, G.

    1985-07-01

    The status of the erythrocyte sodium pump was evaluated in a group of patients suffering from anorexia nervosa and a group of healthy female control subjects. Anorectic patients showed significantly higher mean values of digoxin-binding sites/cell (ie, the number of Na-K-ATPase units) with respect to control subjects while no differences were found in the specific /sup 86/Rb uptake (which reflects the Na-K-ATPase activity) between the two groups. A significant correlation was found between relative weight and the number of Na-K-ATPase pump units (r = -0.66; P less than 0.0001). Anorectic patients showed lower serum T3 concentrations (71.3 +/- 53 ng/dL) with respect to control subjects (100.8 +/- 4.7 ng/dL; P less than 0.0005) and a significant negative correlation between T3 levels and the number of pump units (r = -0.52; P less than 0.003) was found. This study therefore shows that the erythrocyte Na-K pump may be altered in several anorectic patients. The authors suggest that this feature could be interrelated with the degree of underweight and/or malnutrition.

  3. Erythrocyte endogenous proteinase activity during blood bank storage.

    Science.gov (United States)

    de Angelis, V; de Matteis, M C; Orazi, B M; Santarossa, L; Della Toffola, L; Raineri, A; Vettore, L

    1990-01-01

    We studied proteolytic alterations of membrane proteins in ghosts derived from human red blood cells, preserved up to 35 days in the liquid state either as whole blood or with additive solution. The study was carried out by performing sodium dodecyl sulfate polyacrylamide gel electrophoresis of stromal proteins from erythrocytes, either previously treated with proteinase inhibitors or previously incubated in conditions promoting proteolysis. To differentiate the effect of erythrocyte from granulocyte proteinases, the investigation was also carried out in leukocyte-free red cell preparations. The results show: (1) the effects of endogenous proteinases on membrane proteins derived from red cells stored under blood bank conditions; (2) a decrease of proteolytic effects in ghosts derived from red cells which have been submitted to a longer storage; (3) a relevant influence of the red cell resuspending medium before lysis on the time-dependent onset and exhaustion of proteolysis in ghosts. The presence of increased proteolysis in ghosts could be regarded as a marker of molecular lesions induced in red cells by storage under blood bank conditions.

  4. Blood-group-Ii-active gangliosides of human erythrocyte membranes

    International Nuclear Information System (INIS)

    Feizi, T.; Childs, R.A.; Hakomori, S.-I.; Powell, M.E.

    1978-01-01

    More than ten new types of gangliosides, in addition to haematoside and sialosylparagloboside, were isolated from human erythrocyte membranes. These were separated by successive chromatographies on DAEA-Sephadex, on porous silica-gel columns and on thin-layer silica gel as acetylated compounds. Highly potent blood-group-Ii and moderate blood-group-H activities were demonstrated in some of the ganglioside fractions. The gangliosides incorporated into chlolesterol/phosphatidylcholine liposomes stoicheiometrically inhibited binding of anti-(blood-group-I and i) antibodies to a radioiodinated blood-group-Ii-active glycoprotein. The fraction with the highest blood-group-I activity, I(g) fraction, behaved like sialosyl-deca- to dodeca-glycosylceramides on t.l.c. Certain blood-group-I and most of the i-determinants were in partially or completely cryptic form and could be unmasked by sialidase treatment. Thus the I and i antigens, which are known to occur on internal structures of blood-group-ABH-active glycoproteins in secretions, also occur in the interior of the carbohydrate chains of erythrocyte gangliosides. (author)

  5. [Erythrocyte blood groups and geographic pathology (author's transl)].

    Science.gov (United States)

    Salmon, C

    1979-01-01

    Blood groups are an obstacle to reproduction, transfusion and transplantation. There are immunological abortions due to the antibodies of "p" phenotype women; and Rh haemolytic disease of the new-born is in direct proportion to the frequency of the "r" gene in a given population; the problem of transfusional allo-immunisation is completely parallel. Certain membrane anomalies (due to exceptional erythrocyte blood groups--Rh null, Rh mod or McLeod, for example), can provoke hemolytic anaemias, but in these cases the subjects are scattered throughout the world. An important problem is that of the relationships between Duffy antigens and malaria: from what is known about plasmodium Knowlesi, Fya and Fyb antigens are related to the erythrocyte receptors for this plasmodium: the Fy(a-b-) red cells, even of exceptional non-blacks, are not infested with parasites. Two kinds of receptors are postulated: one for adherence and another for penetration. In contrast, plasmodium falciparum does not recognise the same receptors as plasmodium Knowlesi. Experiments carried out on man have led to the conclusion that plasmodium vivax also used Fya and Fyb antigens to penetrate the red cell. These recent facts give rise to the problem of a possible natural selection by plasmodium vivax, which would eradicate polymorphism, whilst until now, the facts concerning plasmodium falciparum have explained the balance of polymorphism.

  6. Modulation of Erythrocyte Plasma Membrane Redox System Activity by Curcumin

    Directory of Open Access Journals (Sweden)

    Prabhakar Singh

    2016-01-01

    Full Text Available Plasma membrane redox system (PMRS is an electron transport chain system ubiquitously present throughout all cell types. It transfers electron from intracellular substrates to extracellular acceptors for regulation of redox status. Curcumin, isolated from Curcuma longa, has modulatory effects on cellular physiology due to its membrane interaction ability and antioxidant potential. The present study investigates the effect of curcumin on PMRS activity of erythrocytes isolated from Wistar rats in vitro and in vivo and validated through an in silico docking simulation study using Molegro Virtual Docker (MVD. Effects of curcumin were also evaluated on level of glutathione (GSH and the oxidant potential of plasma measured in terms of plasma ferric equivalent oxidative potentials (PFEOP. Results show that curcumin significantly (p<0.01 downregulated the PMRS activity in a dose-dependent manner. Molecular docking results suggest that curcumin interacts with amino acids at the active site cavity of cytochrome b5 reductase, a key constituent of PMRS. Curcumin also increased the GSH level in erythrocytes and plasma while simultaneously decreasing the oxidant potential (PFEOP of plasma. Altered PMRS activity and redox status are associated with the pathophysiology of several health complications including aging and diabetes; hence, the above finding may explain part of the role of curcumin in health beneficial effects.

  7. The relationship of element contents in erythrocyte with thyroid function

    International Nuclear Information System (INIS)

    Zhu Li; Zhao Zhiying; Wang Zhenghua; Li Yanfen; Liu Nianqing; Liu Pingsheng; Xu qing; Liu Peng; Qian Qingfang

    1998-01-01

    The serum thyroid hormones (T 3 , T 4 , TSH, FT 3 and FT 4 ) level and the elements K, Ca, Fe, Cu, Zn, Se and Rb in the erythrocyte in 76 cases is measured by radiometric assay in vitro (RIA and IRMA) and nuclear analytical technique (PIXE and INNA). According to thyroid hormones level, the cases are divided into four groups with hyperthyroid, normal, subhyperthyroid and hypothyroid. The difference and correlation of various parameters in four groups are compared by Oneway-ANOVA and Partial Correlation using SPSS/PC statistical package respectively. The results show that the content of Zn for hypothyroid group is significantly higher than hyperthyroid (P = 0.007) and sub-hyperthyroid (P = 0.046) groups, and the content of Zn for normal is lower than hypothyroid group but not significant difference (P = 0.083), the other elements contents are no significant difference among four groups. The highly significant linear correlation between the contents of K, Zn and Cu in the erythrocyte and T 3 , T 4 level ratio and TSH level is observed in hypothyroid and normal groups, the close correlation between the content of Se and serum T 4 and TSH level is also observed in hyperthyroid and sub-hyperthyroid groups. These suggest that trace elements may be important for the synthesis, metabolism and biological function of thyroid hormones

  8. Erythrocyte membrane stabilization effect and antioxidant activity of methyl methacrylate

    International Nuclear Information System (INIS)

    Popov, B.

    2004-01-01

    Methyl methacrylate (MMK) is a synthetic product with mild impact on human health that is not well studied on cellular basis. Here, human erythrocytes were used to investigate the effects MMK exerts on acid and heat-induced hemolysis. Biphasic effect of MMK was observed for acid-induced hemolysis; i.e., protection at low (0 - 0.05% v/v) and stimulation at higher (0.1- 0.4% v/v) concentrations. The maximal protective effect was produced at 0.03% (v/v). At this concentration MMK increased the temperatures of heat denaturation of erythrocyte membrane proteins, spectrin and integral proteins, by about 2 0 C and inhibited the heat-induced hemolysis by 20 %. This membrane stabilization effect of MMK is similar to that produced by some anti-inflammatory and antirheumatic drugs. The increased acid resistance possibly indicated anti-oxidant properties of MMK. The nonenzymatic antioxidant activity test evidenced that MMK has no superoxide dismutase-like activity but demonstrates strong catalase-like activity (about 900 kU/mmol at 0.05-0.1 mmol/l concentration). The results indicate that at low concentration MMK exerts benign effect on cellular membrane that could find therapeutic usage. (author)

  9. Fossilized Mammalian Erythrocytes Associated With a Tick Reveal Ancient Piroplasms.

    Science.gov (United States)

    Poinar, George

    2017-07-01

    Ticks transmit a variety of pathogenic organisms to vertebrates, especially mammals. The fossil record of such associations is extremely rare. An engorged nymphal tick of the genus Ambylomma in Dominican amber was surrounded by erythrocytes from its mammalian host. Some of the exposed erythrocytes contained developmental stages of a hemoprotozoan resembling members of the Order Piroplasmida. The fossil piroplasm is described, its stages compared with those of extant piroplasms, and reasons provided why the mammalian host could have been a primate. The parasites were also found in the gut epithelial cells and body cavity of the fossil tick. Aside from providing the first fossil mammalian red blood cells and the first fossil intraerythrocytic hemoparasites, the present discovery shows that tick-piroplasm associations were already well established in the Tertiary. This discovery provides a timescale that can be used in future studies on the evolution of the Piroplasmida. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com Version of Record, first published online March 20, 2017 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.

  10. Evaluation of Hemagglutination Activity of Chitosan Nanoparticles Using Human Erythrocytes

    Directory of Open Access Journals (Sweden)

    Jefferson Muniz de Lima

    2015-01-01

    Full Text Available Chitosan is a polysaccharide composed of randomly distributed chains of β-(1-4 D-glucosamine and N-acetyl-D-glucosamine. This compound is obtained by partial or total deacetylation of chitin in acidic solution. The chitosan-based hemostatic agents have been gaining much attention in the management of bleeding. The aim of this study was to evaluate in vitro hemagglutination activity of chitosan nanoparticles using human erythrocytes. The preparation of nanoparticles was achieved by ionotropic gelification technique followed by neutralization with NaOH 1 mol/L−1. The hemagglutination activity was performed on a solution of 2% erythrocytes (pH 7.4 on PBS collected from five healthy volunteers. The hemolysis determination was made by spectrophotometric analysis. Chitosan nanoparticle solutions without NaOH addition changed the reddish colour of the wells into brown, suggesting an oxidative reaction of hemoglobin and possible cell lysis. All neutralized solutions of chitosan nanoparticles presented positive haemagglutination, without any change in reaction color. Chitosan nanoparticles presented hemolytic activity ranging from 186.20 to 223.12%, while neutralized solutions ranged from 2.56 to 72.54%, comparing to distilled water. Results highlight the need for development of new routes of synthesis of chitosan nanoparticles within human physiologic pH.

  11. In Vivo distribution of hydrocortisone over whole blood : A novel method for the extraction of erythrocytes

    NARCIS (Netherlands)

    Driessen, O.; Treuren, L.; Moolenaar, A.; Meijer, J.W.A.; Verheijen, P.

    1990-01-01

    Ten mg hydrocortisone (HC) was administered intravenously to a healthy volunteer after a dexamethasone suppresion test and HC concentrations were determined from 1-270 min in plasma, plasma water and on erythrocytes. HC was extracted front erythrocyte concentrates with high efficiency by HC-poor

  12. Method for in vitro labelling of erythrocytes with 99mTc-pertechnetate

    International Nuclear Information System (INIS)

    Kostadinova, I.D.; Hadzhikostova, H.K.; Shejretova, E.T.; Garcheva-Tsacheva, M.B.

    1987-01-01

    The method is easy to apply and gives a possibility to lead the radiopharmaceutical directly to erythrocytes. It includes: blocking of the structures accumulating 99m Tc-pertechnetate by potassium perchlorite; attenuation of the erythrocytes by an intervenous injection of tin pyrophosphate; preparation of the necessary blood quantity with acidum citricum dextrose mixing with 99m Tc-pertechnetate and reinjection. 1 cl

  13. Complement and Antibody-Mediated Enhancement of Erythrocyte Invasion by Plasmodium Falciparum

    Science.gov (United States)

    2016-04-01

    Haynes, J.D., Moch , J.K., Smoot, D.S., 2002. Erythrocytic malaria growth or invasion inhibi- tion assays with emphasis on suspension culture GIA... Moch , J.K., Finberg, R.W., Tsokos, G.C., Stoute, J.A., 2010. Complement receptor 1 is a sialic acid-independent erythrocyte receptor of Plasmodium

  14. Comparative studies on osmosis based encapsulation of sodium diclofenac in porcine and outdated human erythrocyte ghosts.

    Science.gov (United States)

    Bukara, Katarina; Drvenica, Ivana; Ilić, Vesna; Stančić, Ana; Mišić, Danijela; Vasić, Borislav; Gajić, Radoš; Vučetić, Dušan; Kiekens, Filip; Bugarski, Branko

    2016-12-20

    The objective of our study was to develop controlled drug delivery system based on erythrocyte ghosts for amphiphilic compound sodium diclofenac considering the differences between erythrocytes derived from two readily available materials - porcine slaughterhouse and outdated transfusion human blood. Starting erythrocytes, empty erythrocyte ghosts and diclofenac loaded ghosts were compared in terms of the encapsulation efficiency, drug releasing profiles, size distribution, surface charge, conductivity, surface roughness and morphology. The encapsulation of sodium diclofenac was performed by an osmosis based process - gradual hemolysis. During this process sodium diclofenac exerted mild and delayed antihemolytic effect and increased potassium efflux in porcine but not in outdated human erythrocytes. FTIR spectra revealed lack of any membrane lipid disorder and chemical reaction with sodium diclofenac in encapsulated ghosts. Outdated human erythrocyte ghosts with detected nanoscale damages and reduced ability to shrink had encapsulation efficiency of only 8%. On the other hand, porcine erythrocyte ghosts had encapsulation efficiency of 37% and relatively slow drug release rate. More preserved structure and functional properties of porcine erythrocytes related to their superior encapsulation and release performances, define them as more appropriate for the usage in sodium diclofenac encapsulation process. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Change of properties of erythrocytes membranes in UV-irradiated blood

    International Nuclear Information System (INIS)

    Gromov, A.E.; Vetosh, A.N.; Nikonchuk, N.P.; Perelygin, V.G.; Ruzanov, I.B.

    1986-01-01

    An increase in erythrocyte membrane permeability for gases, decrease in erythrocyte thermal stability and activation of membrane transport systems after autotransfusion of UV-irradiated blood are ascertained. The data obtained testify to the fact that the greatest changes in membranes take place not directly under irradiation but after the introduction of irradiated blood to the organism

  16. Triggers, Inhibitors, Mechanisms, and Significance of Eryptosis: The Suicidal Erythrocyte Death

    Directory of Open Access Journals (Sweden)

    Elisabeth Lang

    2015-01-01

    Full Text Available Suicidal erythrocyte death or eryptosis is characterized by erythrocyte shrinkage, cell membrane blebbing, and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include Ca2+ entry, ceramide formation, stimulation of caspases, calpain activation, energy depletion, oxidative stress, and dysregulation of several kinases. Eryptosis is triggered by a wide variety of xenobiotics. It is inhibited by several xenobiotics and endogenous molecules including NO and erythropoietin. The susceptibility of erythrocytes to eryptosis increases with erythrocyte age. Phosphatidylserine exposing erythrocytes adhere to the vascular wall by binding to endothelial CXC-Motiv-Chemokin-16/Scavenger-receptor for phosphatidylserine and oxidized low density lipoprotein (CXCL16. Phosphatidylserine exposing erythrocytes are further engulfed by phagocytosing cells and are thus rapidly cleared from circulating blood. Eryptosis eliminates infected or defective erythrocytes thus counteracting parasitemia in malaria and preventing detrimental hemolysis of defective cells. Excessive eryptosis, however, may lead to anemia and may interfere with microcirculation. Enhanced eryptosis contributes to the pathophysiology of several clinical disorders including metabolic syndrome and diabetes, malignancy, cardiac and renal insufficiency, hemolytic uremic syndrome, sepsis, mycoplasma infection, malaria, iron deficiency, sickle cell anemia, thalassemia, glucose 6-phosphate dehydrogenase deficiency, and Wilson’s disease. Facilitating or inhibiting eryptosis may be a therapeutic option in those disorders.

  17. A numerical two layer model for blood oxygenation in lungs

    International Nuclear Information System (INIS)

    Aminatai, A.

    2001-01-01

    In the modelling of the simultaneous transport of O 2 and CO 2 in the pulmonary circulation described in our earlier studies, the blood has been treated as a homogeneous layer of haemoglobin solution. Since the size of the erythrocyte is not negligible in comparison with that of the capillary, the blood can no longer be considered as a homogeneous fluid and hence, It is worthwhile to consider the blood flow as a two-phase flow consisting of cells and plasma. In the present study, the heterogeneous nature of blood has been proposed by considering the axial train model for the flow [whitmore (1967)], in order to analyze the effect of cell free plasma layer on the process of blood oxygenation in pulmonary capillaries. The proposed model consists of a core of suspended erythrocytes surrounded by a cell free plasma layer near the wall. The coupled system of convective diffusion equaions together with the physiologically relevant boundary, entrance and interface conditions is solved numerically by a four-point semi-implicit scheme to gether with a fixed point iterative technique. The distance traversed by the blood before getting fully oxygenated is computed. It is shown that the core haematocrit and the thickness of the cell depleted layer affect the oxygenation process significantly. It is found that (i) oxygen takes longest and carbondioxide is the fastest to attain equilibraton, (ii) the blood is completely oxygenated within one-fifth part of its transit and (iii) the rate of oxygenation is smaller in case of homogeneous model than that in heterogenous model in the capillary. Finally, the effect of various physiological parameters on the rate of oxygenation has been examined

  18. Hemolitic action of Naja naja atra cardiotoxin on erythrocytes from different animals

    Directory of Open Access Journals (Sweden)

    J. C. Troiano

    2006-01-01

    Full Text Available A comparative study on the sensitivity of erythrocytes from different vertebrate species (avian, mammalian and reptilian to the hemolytic action caused by cardiotoxin isolated from Naja naja atra venom was carried out. Cardiotoxin was able to induce direct hemolysis in washed erythrocytes from several animals, except for llama. The EC50 values from hemolysis of the most sensitive (cat and the most resistant (snake animal varied approximately tenfold. According to the cell behavior, it was possible to characterize four types of behavior: The first was observed in cat, horse and human cells; the second in rat, rabbit and dog erythrocytes; and the third only in llama erythrocytes, which were resistant to cardiotoxin concentrations up to 300 µg/ml. Finally, avian and reptilian erythrocytes were more resistant to cardiotoxin III-induced hemolysis than those of the mammalian species.

  19. Morphological Effects and Antioxidant Capacity of Solanum crispum (Natre) In Vitro Assayed on Human Erythrocytes.

    Science.gov (United States)

    Suwalsky, Mario; Ramírez, Patricia; Avello, Marcia; Villena, Fernando; Gallardo, María José; Barriga, Andrés; Manrique-Moreno, Marcela

    2016-06-01

    In order to gain insight into the molecular mechanism of the antioxidant properties of Solanum crispum, aqueous extracts of its leaves were assayed on human erythrocytes and molecular models of its membrane. Phenolics and alkaloids were detected by HPLC-MS. Scanning electron and defocusing microscopy showed that S. crispum changed erythrocytes from the normal shape to echinocytes. These results imply that molecules present in the aqueous extracts were located in the outer monolayer of the erythrocyte membrane. Dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) were chosen as representative of phospholipid classes located in the outer and inner monolayers of the erythrocyte membrane, respectively. X-ray diffraction showed that S. crispum preferentially interacted with DMPC bilayers. Experiments regarding its antioxidant properties showed that S. crispum neutralized the oxidative capacity of HClO on DMPE bilayers; defocusing microscopy and hemolysis assays demonstrated the protective effect of S. crispum against the oxidant effects of HClO on human erythrocytes.

  20. Isolation of low-molecular-weight lead-binding protein from human erythrocytes

    International Nuclear Information System (INIS)

    Raghavan, S.R.V.; Gonick, H.C.

    1977-01-01

    In blood, lead is mainly associated with erythrocytes and only a very small amount is found in plasma. Previously it was thought that the lead was bound to the erythrocyte cell membrane but more recently it has been observed that lead is bound primarily to the cell contents, ostensibly hemoglobin. In examining the lead-binding properties of normal human erythrocytes and those of lead-exposed industrial workers, we have found that, whereas lead binds only to hemoglobin in normal erythrocytes, there is also appreciable binding of lead to a low-molecular weight-protein in erythrocytes from lead-exposed workers. The synthesis of this protein may be induced by lead exposure. The 10,000 molecular weight protein may act as a storage site and mechanism for segregating lead in a non-toxic form

  1. A rapid method for counting nucleated erythrocytes on stained blood smears by digital image analysis

    Science.gov (United States)

    Gering, E.; Atkinson, C.T.

    2004-01-01

    Measures of parasitemia by intraerythrocytic hematozoan parasites are normally expressed as the number of infected erythrocytes per n erythrocytes and are notoriously tedious and time consuming to measure. We describe a protocol for generating rapid counts of nucleated erythrocytes from digital micrographs of thin blood smears that can be used to estimate intensity of hematozoan infections in nonmammalian vertebrate hosts. This method takes advantage of the bold contrast and relatively uniform size and morphology of erythrocyte nuclei on Giemsa-stained blood smears and uses ImageJ, a java-based image analysis program developed at the U.S. National Institutes of Health and available on the internet, to recognize and count these nuclei. This technique makes feasible rapid and accurate counts of total erythrocytes in large numbers of microscope fields, which can be used in the calculation of peripheral parasitemias in low-intensity infections.

  2. Alterations of erythrocyte rheology and cellular susceptibility in end stage renal disease: Effects of peritoneal dialysis.

    Directory of Open Access Journals (Sweden)

    Nesrin Zeynep Ertan

    Full Text Available In this study, we investigated the effects of peritoneal dialysis on hemorheological and hematological parameters and their relations with oxidant and antioxidant status of uremic patients. Hemorheological parameters (erythrocyte deformability, erythrocyte aggregation, osmotic deformability, blood and plasma viscosity were measured in patients with renal insufficiency undergoing peritoneal dialysis (PD and volunteers. Erythrocyte deformability, osmotic deformability and aggregation in both autologous plasma and 3% dextran 70 were measured by laser diffraction ektacytometry. Enzyme activities of glutathione peroxidase, superoxide dismutase and catalase were studied in erythrocytes; lipid peroxidation was studied by measuring the amount of malondialdehyde in both erythrocytes and plasma samples. Blood viscosity at native hematocrit was significantly lower in PD patients at all measured shear rates compared to controls, but it was high in PD patients at corrected (45% hematocrit. Erythrocyte deformability did not show any difference between the two groups. Osmotic deformability was significantly lower in PD patients compared to controls. Aggregation index values were significantly high in PD patients in plasma Catalase and glutathione peroxidase activities in erythrocytes were decreased in PD patients whereas superoxide dismutase activity was increased compared to controls. Malondialdehyde was significantly increased in erythrocytes and plasma samples of PD patients which also shows correlations with aggregation parameters. It has been concluded that erythrocytes in PD patients are more prone to aggregation and this tendency could be influenced by lipid peroxidation activity in patient's plasma. These results imply that uremic conditions, loss of plasma proteins and an increased risk of oxidative stress because of decreasing levels of antioxidant enzymes affect erythrocyte rheology during peritoneal dialysis. This level of distortion may have

  3. Evaluation of a new pulse oximeter sensor.

    Science.gov (United States)

    Fernandez, Marco; Burns, Kathy; Calhoun, Beverly; George, Saramma; Martin, Beverly; Weaver, Chris

    2007-03-01

    A new forehead noninvasive oxygen saturation sensor may improve signal quality in patients with low cardiac index. To examine agreement between oxygen saturation values obtained by using digit-based and forehead pulse oximeters with arterial oxygen saturation in patients with low cardiac index. A method-comparison study was used to examine the agreement between 2 different pulse oximeters and arterial oxygen saturation in patients with low cardiac index. Readings were obtained from a finger and a forehead sensor and by analysis of a blood sample. Bias, precision, and root mean square differences were calculated for the digit and forehead sensors. Differences in bias and precision between the 2 noninvasive devices were evaluated with a t test (level of significance P<.05). Nineteen patients with low cardiac index (calculated as cardiac output in liters per minute divided by body surface area in square meters; mean 1.98, SD 0.34) were studied for a total of 54 sampling periods. Mean (SD) oxygen saturations were 97% (2.4) for blood samples, 96% (3.2) for the finger sensor, and 97% (2.8) for the forehead sensor. By Bland Altman analysis, bias +/- precision was -1.16 +/- 1.62% for the digit sensor and -0.36 +/- 1.74% for the forehead sensor; root mean square differences were 1.93% and 1.70%, respectively. Bias and precision differed significantly between the 2 devices; the forehead sensor differed less from the blood sample. In patients with low cardiac index, the forehead sensor was better than the digit sensor for pulse oximetry.

  4. Effect of thiol reactive reagents and ionizing radiation on the permeability of erythrocyte membrane for non-electrolyte spin labels

    International Nuclear Information System (INIS)

    Gwozdzinski, K.

    1986-01-01

    The paper presents some results on the effect of PCMB and NEM on the transport of non-electrolyte spin labels: TEMPO and TEMPOL across non-irradiated and irradiated porcine erythrocyte. Irradiated erythrocytes exhibited increased inhibitory effect of thiol reactive compounds in the TEMPO and TEMPOL transport compared to non-irradiated erythrocytes. (orig.)

  5. Sensors, Volume 4, Thermal Sensors

    Science.gov (United States)

    Scholz, Jorg; Ricolfi, Teresio

    1996-12-01

    'Sensors' is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This volume describes the construction and applicational aspects of thermal sensors while presenting a rigorous treatment of the underlying physical principles. It provides a unique overview of the various categories of sensors as well as of specific groups, e.g. temperature sensors (resistance thermometers, thermocouples, and radiation thermometers), noise and acoustic thermometers, heat-flow and mass-flow sensors. Specific facettes of applications are presented by specialists from different fields including process control, automotive technology and cryogenics. This volume is an indispensable reference work and text book for both specialists and newcomers, researchers and developers.

  6. Relation of erythrocyte and iron indices to oral cancer growth

    International Nuclear Information System (INIS)

    Bhattathiri, Vasudevaru Narayanan

    2001-01-01

    Background and purpose: Anaemia is known to influence prognosis of head and neck cancer patients, but how anaemia and tumour growth influences each other is not clear. The present study investigates the relation of erythrocyte and iron indices of oral cancer patients to primary tumour size (Tsize), invasiveness and lymph node involvement. Materials and methods: The haemoglobin (Hb), erythrocyte count (RBC), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), Serum iron (SFe), transferrin iron-binding capacity (TIBC) and transferrin saturation (%Fe) were evaluated in 217 untreated patients with epidermoid cancer of the bucco-gingivo-palatine area. The association of erythrocyte and iron indices with sex, tumour size groups, invasion of adjacent structures and lymph node involvement, as well as the relation of SFe to Hb were analyzed. Results: Most of the patients were anaemic in terms of Hb (63%), RBC (43%) and PCV (48.4%) but almost all had normal or higher MCH (97.3%) and MCV (93.3%) though MCHC was less than normal in 70.7%. Normal or higher SFe was seen in nearly 70% and TIBC in 45% of patients. Hb, RBC and PCV were significantly lower in women, but there was no difference between men and women in the case of MCV, MCH and MCHC. Primary tumour size showed negative association with Hb, RBC and PCV but positive association with MCH ( 4 cm: 31. 7 pg; P=0.04) and MCHC ( 4 cm: 32.1; P=0.006). MCV, SFe, TIBC and %Fe did not show any relation to primary tumour size. None of the indices had any relation to invasion of adjacent structures or lymph node involvement. MCH, MCHC and MCV were not different in men and women but women had significantly lower Hb, RBC and PCV. The SFe showed poor correlation with Hb. Conclusions: The negative association of Hb, RBC and PCV with tumour size is most likely due to chronic RBC destruction, probably tumour induced, with the products of

  7. Erythrocyte hemolysis by organic tin and lead compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kleszcynska, H. [Agricultural Univ., Wroclaw (Poland). Dept. of Physics and Biophysics; Hladyszowski, J. [Agricultural Univ., Wroclaw (Poland). Dept. of Physics and Biophysics; Pruchnik, H. [Agricultural Univ., Wroclaw (Poland). Dept. of Physics and Biophysics; Przestalski, S. [Agricultural Univ., Wroclaw (Poland). Dept. of Physics and Biophysics

    1997-01-01

    The effect of trialkyllead and trialkyltin on pig erythrocyte hemolysis has been studied and compared. The results of experiments showed that the hemolytic activity of organoleads increases with their hydrophobicity and follows the sequence: triethyllead chloride < tri-n-propyllead chloride < tributyllead chloride. And similarly in the case of organotins: triethyltin chloride < tri-n-propyltin chloride < tributyltin chloride. Comparison of the hemolytic activity of organoleads and organotins indicates that the lead compounds exhibit higher hemolytic activity. The methods of quantum chemistry allowed to determine the maximum electric potential of the ions R{sub 3}Pb{sup +} and R{sub 3}Sn{sup +}, and suggest a relationship between the potential and toxicity. (orig.)

  8. Action of certain chemical compounds on radiation haemolysis of erythrocytes

    International Nuclear Information System (INIS)

    Kolesnikov, Yu.A.; Shulgina, M.A.; Yartsev, E.I.; Novoseltseva, S.D.; Bogatyrev, G.P.

    1975-01-01

    A radioprotective action of a number of protective chemicals on radiation haemolysis of erythrocytes has been studied. S-bearing radioprotectors, serotonin and arginine possess the highest radioprotective activity. The same radioprotectors delivered to the medium after irradiation do not influence the development of the post-irradiation haemolysis. Certain amino acids, namely proline, serine and taurine have a pronounced radio-protective action when given to the medium after irradiation, taurine producing the strongest effect on the development of radiation haemolysis. The mechanism of action of these substances is unrelated to the increased osmotic pressure of the medium and might be explained by normalization of the functional state of cytomembranes and processes of cell metabolism

  9. Erythrocyte sedimentation as detected by He:Ne laser

    International Nuclear Information System (INIS)

    Abdulla, M. M.; Al-Ani, F. S.; Al-Ani, A.

    2005-01-01

    Aggregation of erythrocytes is a reversable dynamic process. The growth process of three dimensional - chain - like aggregates depends on the shape of the cell available for the attachment. A study of red blood cell aggregation and sedimentation was performed for sample of 5% and 10% red blood cells in plasma, with macromolecules and without macromolecules. The analysis was studied under dynamic conditions by applying the method of back scattering laser light. The aggregation and reorientation of red blood cells was recorded via X-Y recorder connected to a sensitive photo diode. The records decleared the phases of the process as a function of time and amplitude. The amplitude of light signal depends on the size of aggregates and concentration of sample. The time intervals of different phases of aggregation and sedimentation were measured and the contribution of macromolecule substance in the plasma was analysed. (author)

  10. Erythrocytic glutathione peroxidase: Its relationship to plasma selenium in man

    International Nuclear Information System (INIS)

    Perona, G.; Cellerino, R.; Guidi, G.C.; Moschini, G.; Stievano, B.M.; Tregnaghi, C.

    1977-01-01

    Erythrocytic glutathione-peroxidase (GSH-Px) activity and plasma selenium concentrations were measured in 14 patients: 7 with iron deficiency and 7 with raised serum iron levels. The decreased enzymatic activity in iron deficiency was confirmed. Plasma selenium was significantly lower in patients with lower serum iron; furthermore there is a significant correlation between serum iron and plasma selenium concentrations. Another correlation even more significant was found between plasma selenium and enzyme activity in all the cases we studied. These data suggests that the importance of iron for GSH-Px activity may be merely due to its relationship with selenium and that plasma selenium concentration may be of critical importance for enzyme activity. (author)

  11. Solubilization of human erythrocyte membranes by ASB detergents

    Directory of Open Access Journals (Sweden)

    C.C. Domingues

    2008-09-01

    Full Text Available Understanding the membrane solubilization process and finding effective solubilizing agents are crucial challenges in biochemical research. Here we report results on the interaction of the novel linear alkylamido propyl dimethyl amino propanosulfonate detergents, ASB-14 and ASB-16, with human erythrocyte membranes. An estimation of the critical micelle concentration of these zwitterionic detergents (ASB-14 = 100 µM and ASB-16 = 10 µM was obtained using electron paramagnetic resonance. The amount of proteins and cholesterol solubilized from erythrocytes by these detergents was then determined. The hemolytic activities of the ASB detergents were assayed and the detergent/lipid molar ratios for the onset of hemolysis (Re sat and total lysis (Re sol were calculated, allowing the determination of the membrane binding constants (Kb. ASB-14 presented lower membrane affinity (Kb = 7050 M-1 than ASB-16 (Kb = 15610 M-1. The amount of proteins and cholesterol solubilized by both ASB detergents was higher while Re sat values (0.22 and 0.08 detergent/lipid for ASB-14 and ASB-16, respectively were smaller than those observed with the classic detergents CHAPS and Triton X-100. These results reveal that, besides their well-known use as membrane protein solubilizers to enhance the resolution of two dimensional electrophoresis/mass spectrometry, ASB-14 and ASB-16 are strong hemolytic agents. We propose that the physicochemical properties of ASB detergents determine their membrane disruption efficiency and can help to explain the improvement in the solubilization of membrane proteins, as reported in the literature.

  12. Labelling malaria-infected human erythrocytes with Tc-99m

    International Nuclear Information System (INIS)

    Garmelius-Larsson, B.; Pettersson, F.; Vogt, A.; Jonsson, C.

    2002-01-01

    Aim: Malaria is an old and a very common disease, especially in undeveloped countries. The malaria parasites infect the erythrocytes and the aim of this work was to label infected cells for future studies of their distribution and life span. Material and Method: With a commercial kit containing stannous fluoride and sodium medronate, which is used to label erythrocytes in vivo, in vitro and in vivo/vitro methods, we labelled the cells by using a modified method and a small volume, 5 - 50 microlitre, of packed cells. The cells were labelled with Tc-99m in the range of 60 - 1500 MBq. The kit was reconstituted with saline and the pH was adjusted to 7.0. The cells were incubated with 1 ml of the kitsolution in 37 0 C for 5 min. The remaining Sn-ions were reduced by adding NaOCl and then the solution was centrifuged.The supernantant was discarded and the Tc-99m was added to the precipitate and incubated 37 0 C for 20 min and then washed 3 times. This labelling procedure was performed on both infected and on non-infected cells. Results: Ten samples of cells have been labelled. The best labelling result was obtained using 7 - 20 MBq per 10 microlitre of packed cells. The labelling efficiency was, on average, 35%. Conclusion: It is possible to label both infected and non-infected cells in very small volumes. The cells were visually inspected in a microscope and were viable after labelling. Furthermore, the cell distribution was traced in vivo in an animal model by a gamma camera

  13. The role of primary lymphoid organs of chickens in the elimination of 51Cr-labelled erythrocytes

    International Nuclear Information System (INIS)

    Hala, K.; Schulmannova, J.; Nemeckova, S.

    1980-01-01

    F 1 chicken hybrids of the inbred lines CC and IC were injected erythrocytes from CB line chickens (differing in alloantigens of the major histocompatibility system B) or IA line chickens (differing in the A blood group system alloantigens). Injected erythrocytes were labelled with 51 Cr and their gradual elimination from the recipient's circulation was checked. Surgical bursectomy was performed at the end of embryogenesis and thymectomy immediately after hatching. Bursectomy prolonged the survival of B- and A-incompatible erythrocytes. Thymectomy prolonged the survival of A-incompatible erythrocytes and had no effect on the elimination of erythrocytes possessing B antigens. (author)

  14. Loss of the clock protein PER2 shortens the erythrocyte life span in mice.

    Science.gov (United States)

    Sun, Qi; Zhao, Yue; Yang, Yunxia; Yang, Xiao; Li, Minghui; Xu, Xi; Wen, Dan; Wang, Junsong; Zhang, Jianfa

    2017-07-28

    Cell proliferation and release from the bone marrow have been demonstrated to be controlled by circadian rhythms in both humans and mice. However, it is unclear whether local circadian clocks in the bone marrow influence physiological functions and life span of erythrocytes. Here, we report that loss of the clock gene Per2 significantly decreased erythrocyte life span. Mice deficient in Per2 were more susceptible to acute stresses in the erythrocytes, becoming severely anemic upon phenylhydrazine, osmotic, and H 2 O 2 challenges. 1 H NMR-based metabolomics analysis revealed that the Per2 depletion causes significant changes in metabolic profiles of erythrocytes, including increased lactate and decreased ATP levels compared with wild-type mice. The lower ATP levels were associated with hyperfunction of Na + /K + -ATPase activity in Per2 -null erythrocytes, and inhibition of Na + /K + -ATPase activity by ouabain efficiently rescued ATP levels. Per2 -null mice displayed increased levels of Na + /K + -ATPase α1 (ATP1A1) in the erythrocyte membrane, and transfection of Per2 cDNA into the erythroleukemic cell line TF-1 inhibited Atp1a1 expression. Furthermore, we observed that PER2 regulates Atp1a1 transcription through interacting with trans-acting transcription factor 1 (SP1). Our findings reveal that Per2 function in the bone marrow is required for the regulation of life span in circulating erythrocytes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. THE IMPORTANCE OF THE ERYTHROCYTES OSMOTIC FRAGILITY TEST PERFORMED IN CHILDREN WITH INDIRECT HYPERBILIRUB1NEMIA

    Directory of Open Access Journals (Sweden)

    Ivana Stojanović

    2005-07-01

    Full Text Available The osmotic fragility test of erythrocytes is useful in the diagnosis of different types of hereditary hemolytic anemias followed with hyperbilirubinemia. Hemolytic anemias, characterized by accelerated destruction of red blood cells, are usually the consequence of many metabolic abnormalities like cellular membrane defect, erythrocyte enzymes defect or hemoglobin abnormalities – hemoglobinopathies. The object of our study was to assess the relationship between osmotic fragility test of erythrocytes and severity of indirect hyperbilirubinemia in some inherited erythrocytes’ disorders. We did the osmotic fragility test of erythrocytes by using Dacie, s method with normal values of erythrocytes hemolysis between 0,48 to 0,34% NaCl (minimal to maximal hemolysis. In hereditary spherocytosis, fragility of erythrocytes was increased (min. at 0,50 % NaCl to max. 0,44 % NaCl . In the child with β- thalassemia and cycle cell anemia erythrocytes fragility was decreased (min . at 0,42 to max. 0,32 % NaCl, that is 0,40% min. of hemolysis and 0,34% max. hemolysis in the second case. In newborn infants with high levels of indirect bilirubin in serum as a cause of physiological jaundice, the osmotic fragility test was within a normal range. Our findings point out the diagnostic value of osmotic fragility test in assessing patients with the indirect hyperbilirubinemia. This simple and important diagnostic test can be performed in small laboratories.

  16. Hereditary spherocytosis and elliptocytosis associated with prosthetic heart valve replacement: rheological study of erythrocyte modifications.

    Science.gov (United States)

    Caprari, Patrizia; Tarzia, Anna; Mojoli, Giorgio; Cianciulli, Paolo; Mannella, Emilio; Martorana, Maria Cristina

    2009-04-01

    The implantation of a prosthetic heart valve (HVP) in patients with hereditary spherocytosis (HS) and hereditary elliptocytosis (HE) is rare, and the changes in the structure and deformability of erythrocytes that follow implantation in these patients have been poorly described. In the present study, the erythrocytes in HS and HE patients with mechanical HVP were compared to the erythrocytes in patients with only congenital membrane defects, in terms of biochemical modifications and rheological behaviour. Integral and cytoskeletal erythrocyte membrane proteins were studied, and blood viscosity (shear rate/shear stress ratio), aggregation ratio [eta(1 s(-1))/eta(200 s(-1))], and red cell visco-elasticity were determined. Valve replacement with a mechanical prosthesis worsened anaemia and resulted in a change in haemolysis, from sub-clinical to evident. The rheological investigation of erythrocytes from HS patients confirmed the characteristic increased viscosity and aggregation ratio and the decreased deformability. The rheological behaviour of erythrocytes from patients with HVP showed a decrease in viscosity and an increase in elastic modulus. In these patients, the prosthesis seems to have induced traumatic damage to the erythrocyte membrane, leading to fragmentation and lysis, which in turn modified rheological parameters. The biochemical and rheological investigation allowed us to understand the clinical and haematological pictures of the patients and to describe the role played by different factors in haemolytic anaemia.

  17. The study of the dynamics of erythrocytes under the influence of an external electric field

    Science.gov (United States)

    Mamaeva, Sargylana N.; Maksimov, Georgy V.; Antonov, Stepan R.

    2017-11-01

    A mathematical model is considered for the determination of the surface charge of an erythrocyte with its shape approximated by a surface of revolution of the second order, and the investigation of the dynamics of erythrocytes under the influence of an external electric field. In the first part of this work, the electrical surface charge of the erythrocyte of the patient was calculated with the assumption that the change in the shape and size of the red blood cells leads to stabilization of the electric field, providing a normal electrostatic repulsion. In the second part of the work, the research results of dynamics of changes in the morphology of erythrocytes under the influence of an external electric field depending on the values of their surface charge and resistance of blood plasma is presented. In the course of the work, the dependence of the surface charge of red blood cells from their shape and size is presented. The determination of the relationship between the value of the charge field and the surface of erythrocytes in norm and in pathology is shown. The dependence of the velocity of the erythrocytes on the characteristics of the external electric field, surface charge of the erythrocyte and properties of the medium is obtained. The results of this study can be applied indirectly to diagnose diseases and to develop recommendations for experimental studies of hemodynamics under the influence of various external physical factors.

  18. Lack of Aquaporin 3 in bovine erythrocyte membranes correlates with low glycerol permeation.

    Science.gov (United States)

    Campos, Elisa; Moura, Teresa F; Oliva, Abel; Leandro, Paula; Soveral, Graça

    2011-05-13

    In general, erythrocytes are highly permeable to water, urea and glycerol. However, expression of aquaporin isoforms in erythrocytes appears to be species characteristic. In the present study, human (hRBC) and bovine (bRBC) erythrocytes were chosen for comparative studies due to their significant difference in membrane glycerol permeability. Osmotic water permeability (P(f)) at 23°C was (2.89 ± 0.37) × 10(-2) and (5.12 ± 0.61) × 10(-2)cms(-1) for human and bovine cells, respectively, with similar activation energies for water transport. Glycerol permeability (P(gly)) for human ((1.37 ± 0.26) × 10(-5)cms(-1)) differed in three orders of magnitude from bovine erythrocytes ((5.82 ± 0.37) × 10(-8)cms(-1)) that also showed higher activation energy for glycerol transport. When compared to human, bovine erythrocytes showed a similar expression pattern of AQP1 glycosylated forms on immunoblot analysis, though in slight higher levels, which could be correlated with the 1.5-fold larger P(f) found. However, AQP3 expression was not detectable. Immunofluorescence analysis confirmed the absence of AQP3 expression in bovine erythrocyte membranes. In conclusion, lack of AQP3 in bovine erythrocytes points to the lipid pathway as responsible for glycerol permeation and explains the low glycerol permeability and high E(a) for transport observed in ruminants. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. [The 2,3-diphosphoglycerate shunt and stabilization of the ATP level in mammalian erythrocytes].

    Science.gov (United States)

    Ataullakhanov, A I; Ataullakhanov, F I; Vitvitskiĭ, V M; Zhabotinskiĭ, A M; Pichugin, A V

    1985-06-01

    The mechanisms of regulation of energy metabolism in erythrocytes of various mammalian species were investigated. In native erythrocytes of man, sheep, cow, dog and mouse the dependencies of the rates of glucose uptake on ATP concentration (i.e., regulatory parameters of glycolysis) were measured. These parameters plotted in normalized coordinates are not species-specific (invariant). The dependence of the rate of ATP-consuming processes on ATP concentration has been studied for the first time in intact mammalian erythrocytes. This dependence was found to be linear only in the species, in whose erythrocytes the activity of 2,3-diphosphoglycerate shunt is practically zero. In all species under study, the stabilization of ATP level is provided for mainly by the hexokinase-phosphofructokinase system. A comparison of regulatory mechanisms of energy metabolism in mammalian (sheep, cow) erythrocytes, in which the 2,3-diphosphoglycerate shunt is absent, with human and animal erythrocytes, in which this pathway is active, points to the important role of the 2,3-diphosphoglycerate shunt in regulation of energy conversion in erythrocytes. This shunt operates as an additional stabilizer protecting the cell from extremal influences.

  20. Intraspecific variation in erythrocyte sizes among populations of Hypsiboas cordobas (Anura: Hylidae

    Directory of Open Access Journals (Sweden)

    Mariana Baraquet

    2013-12-01

    Full Text Available We studied the morphology and size of erythrocytes of H. cordobae, and analysed the geographic variation of this character along the distribution of the species, in relation to the latitudinal and altitudinal distances. Erythrocyte shape of the H. cordobae is ellipsoidal and the nuclei are also ellipsoidal and centrally oriented. Erythrocyte and nuclear size showed significant differences among populations, with the highest mean size corresponding to the population of Achiras (low altitude site and the lowest mean size to Los Linderos (high altitude site. There was no significant relationship between the latitude of each population and the both erythrocyte and nuclear size. The altitudinal variation in erythrocyte cell size may be attributable to the surface available for gas exchange; a small erythrocyte offers a possibility of greater rate of exchange than a larger one. Our results are consistent with studies of other amphibians, where intraspecific comparisons of populations at different altitudes show that individuals at higher altitudes are characterized by smaller erythrocytes.

  1. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  2. Gas Sensor

    KAUST Repository

    Luebke, Ryan; Eddaoudi, Mohamed; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Salama, Khaled N.

    2015-01-01

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  3. Sensor web

    Science.gov (United States)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  4. The Trw type IV secretion system of Bartonella mediates host-specific adhesion to erythrocytes.

    Directory of Open Access Journals (Sweden)

    Muriel Vayssier-Taussat

    2010-06-01

    Full Text Available Bacterial pathogens typically infect only a limited range of hosts; however, the genetic mechanisms governing host-specificity are poorly understood. The alpha-proteobacterial genus Bartonella comprises 21 species that cause host-specific intraerythrocytic bacteremia as hallmark of infection in their respective mammalian reservoirs, including the human-specific pathogens Bartonella quintana and Bartonella bacilliformis that cause trench fever and Oroya fever, respectively. Here, we have identified bacterial factors that mediate host-specific erythrocyte colonization in the mammalian reservoirs. Using mouse-specific Bartonella birtlesii, human-specific Bartonella quintana, cat-specific Bartonella henselae and rat-specific Bartonella tribocorum, we established in vitro adhesion and invasion assays with isolated erythrocytes that fully reproduce the host-specificity of erythrocyte infection as observed in vivo. By signature-tagged mutagenesis of B. birtlesii and mutant selection in a mouse infection model we identified mutants impaired in establishing intraerythrocytic bacteremia. Among 45 abacteremic mutants, five failed to adhere to and invade mouse erythrocytes in vitro. The corresponding genes encode components of the type IV secretion system (T4SS Trw, demonstrating that this virulence factor laterally acquired by the Bartonella lineage is directly involved in adherence to erythrocytes. Strikingly, ectopic expression of Trw of rat-specific B. tribocorum in cat-specific B. henselae or human-specific B. quintana expanded their host range for erythrocyte infection to rat, demonstrating that Trw mediates host-specific erythrocyte infection. A molecular evolutionary analysis of the trw locus further indicated that the variable, surface-located TrwL and TrwJ might represent the T4SS components that determine host-specificity of erythrocyte parasitism. In conclusion, we show that the laterally acquired Trw T4SS diversified in the Bartonella lineage

  5. Oxygen and carbon dioxide sensing

    Science.gov (United States)

    Ren, Fan (Inventor); Pearton, Stephen John (Inventor)

    2012-01-01

    A high electron mobility transistor (HEMT) capable of performing as a CO.sub.2 or O.sub.2 sensor is disclosed, hi one implementation, a polymer solar cell can be connected to the HEMT for use in an infrared detection system. In a second implementation, a selective recognition layer can be provided on a gate region of the HEMT. For carbon dioxide sensing, the selective recognition layer can be, in one example, PEI/starch. For oxygen sensing, the selective recognition layer can be, in one example, indium zinc oxide (IZO). In one application, the HEMTs can be used for the detection of carbon dioxide and oxygen in exhaled breath or blood.

  6. Radioprotection on nucleated and anucleated erythrocytes by oxide-reduction coenzymes

    International Nuclear Information System (INIS)

    Fernandez, M.; Tomicic, I.; Rojo, I.

    1981-01-01

    The protective effects of NAD, FAD and quinone and mixtures of these compounds were studied on gamma irradiated rabbit and chicken erythrocytes. The dose relative factor (DRF 37) was evaluated by visible absorbancy measurements of liberated hemoglobin. The DRF 37 obtained on rabbit erythrocytes were: NAD+FAD+quinone mixture: 11,1; NAD+ quinone mixture: 6,1; FAD+quinone mixture: 6,1; NAD: 1,6; FAD: 5,5; quinone: 5,1. The DRF 37 obtained with the mixture NAD+FAD+quinone on chicken erythrocytes was 3,9. The high efficiency of the radioprotective mixture NAD+FAD+ quinone is discussed. (author)

  7. Survival of rats subjected to acute anemia at different levels of erythrocyte 2,3-diphosphoglycerate.

    Science.gov (United States)

    Arturson, G; Westman, M

    1975-12-01

    An experimental procedure was worked out in which rats were subjected to an exchange of erythrocytes, followed by acute anemia by means of hemodilution. One group of rats received erythrocytes with a high concentration of 2,3-diphosphoglycerate (DPG), and the other group was given erythrocytes with a low DPG concentration. The survival rate was equal in the two groups. Irrespective of DPG concentration, the rats whose hemoglobin concentration reached the lowest level died. The rats that died were also more acidotic than the others. The results indicate that the hemoglobin concentration and the pH value were more important determinants for survival than the DPG concentrations.

  8. The osmotic fragility of human erythrocytes is inhibited by laser irradiation

    International Nuclear Information System (INIS)

    Habodaszova, D.; Sikurova, L.; Waczulikova, I.

    2004-01-01

    In this study we investigated the influence of green laser irradiation (532 nm, 30 mW, 31,7 J/cm 2 ) on the membrane integrity of human erythrocytes and compared the results with the effect of infrared laser irradiation (810 nm, 50 mW, 31,3 J/cm 2 ). To evaluate the membrane integrity of erythrocytes, one clinical parameter, the osmotic fragility, was investigated. We observed a decrease in osmotic fragility of the erythrocytes after irradiation by the green laser light as well as by the infrared laser compared to non-irradiated controls (Authors)

  9. Unusual bone marrow visualization with sup(99m)Tc-damaged erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Dolgova-Korubin, V; Simova, N

    1982-05-01

    A visualization of the bone marrow and of the spleen was obtained with sup(99m)Tc-labeled N-ethylmaleimide (NEM) damaged erythrocytes in a patient with systemic lupus erythematosus. This phenomenon could be produced both with autologous and homologous red cells. The patient's NEM-damaged erythrocytes given to a healthy patient did not produce a visualization of the marrow. Such an observation was not present in a series of healthy persons and patients with different disorders to whom labeled and damaged erythrocytes were administered, and has not been reported in the literature so far.

  10. Encapsulation of interleukin-2 in murine erythrocytes and subsequent deposition in mice receiving a subcutaneous injection

    International Nuclear Information System (INIS)

    DeLoach, J.R.; Andrews, K.; Sheffield, C.L.

    1988-01-01

    Radiolabeled recombinant human interleukin-2 (IL-2) was successfully encapsulated in both mouse and sheep erythrocytes. Of the added IL-2, 70% was recovered bound to or encapsulated within the carrier cells. Erythrocytes containing IL-2 were stable in vitro and most of the IL-2 remained associated with the cells following a 16-h incubation at 37 degrees C. When carrier erythrocytes containing IL-2 were injected subcutaneously into mice, intact [ 35 S]IL-2 was detectable in a number of tissues 3 days after injection

  11. New Insight into Erythrocyte through In Vivo Surface-Enhanced Raman Spectroscopy

    DEFF Research Database (Denmark)

    Brazhe, Nadezda A.; Abdali, Salim; Brazhe, Alexey R.

    2009-01-01

    containing erythrocytes in their normal physiological environment in a mixture of colloid solution with silver nanoparticles and the procedure for the optimization of SERS conditions to achieve high signal enhancement without affecting the properties of living erythrocytes. By means of three independent...... techniques, we demonstrate that under the proposed conditions a colloid solution of silver nanoparticles does not affect the properties of erythrocytes. For the first time to our knowledge, we describe how to use the SERS-RS approach to study two populations of hemoglobin molecules inside an intact living...

  12. In vivo survival of [14C]sucrose-loaded porcine carrier erythrocytes

    International Nuclear Information System (INIS)

    DeLoach, J.R.

    1983-01-01

    Porcine carrier erythrocyte survival was measured in adult pigs. [14C]Sucrose-loaded erythrocytes had a biphasic survival curve, with as much as 50% of the cells removed from circulation in the first 24 hours. The remaining cells had a 35-day half-life. Encapsulation values were measured for porcine erythrocytes and entrapment of [14C]sucrose was greater than 45%. Addition of inosine and glucose to the dialyzed cells and to the final wash buffer before reinjection of autologous cells did not improve their survival

  13. Ratiometric glucose sensing based on fluorescent oxygen films and glucose oxidase

    OpenAIRE

    Fengyu Su; Liqiang Zhang; Xiangxing Kong; Fred Lee; Yanqing Tian; Deirdre R. Meldrum

    2017-01-01

    A new two-layer sensor film was constructed for sensing glucose based on glucose oxidase and oxygen sensing material. The first layer of film containing the oxygen sensor and intra-reference material was polymerized, then the second layer of glucose oxidase and glutaraldehyde was formed on the oxygen sensor layer. The two-layer sensor film has a resolution up to 0.05 mM and a detection range from 0 to 5 mM to glucose. The effects of pH and temperature on the sensing performance were systemati...

  14. Chemical sensors

    International Nuclear Information System (INIS)

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section

  15. Ratiometric glucose sensing based on fluorescent oxygen films and glucose oxidase

    Directory of Open Access Journals (Sweden)

    Fengyu Su

    2017-06-01

    Full Text Available A new two-layer sensor film was constructed for sensing glucose based on glucose oxidase and oxygen sensing material. The first layer of film containing the oxygen sensor and intra-reference material was polymerized, then the second layer of glucose oxidase and glutaraldehyde was formed on the oxygen sensor layer. The two-layer sensor film has a resolution up to 0.05 mM and a detection range from 0 to 5 mM to glucose. The effects of pH and temperature on the sensing performance were systematically investigated. The selective detection of glucose among other monosaccharides, such as fructose, mannose and galactose indicated that the sensing film has excellent selectivity. The prepared sensor was successfully applied for glucose sample detection of glucose concentration in artificial tears. Keywords: Glucose sensor, Glucose oxidase, Fluorescence, Oxygen film, Diabetes

  16. LUMOS - A Sensitive and Reliable Optode System for Measuring Dissolved Oxygen in the Nanomolar Range

    DEFF Research Database (Denmark)

    Lehner, Philipp; Larndorfer, Christoph; Garcia-Robledo, Emilio

    2015-01-01

    Most commercially available optical oxygen sensors target the measuring range of 300 to 2 mu mol L-1. However these are not suitable for investigating the nanomolar range which is relevant for many important environmental situations. We therefore developed a miniaturized phase fluorimeter based...... for read out of less sensitive optical oxygen sensors based on the same or similar indicator dyes, for example for monitoring oxygen at physiological conditions. The presented sensor system exhibits lower noise, higher resolution and higher sensitivity than the electrochemical STOX sensor previously used...... measurement system called the LUMOS (Luminescence Measuring Oxygen Sensor). It consists of a readout device and specialized "sensing chemistry" that relies on commercially available components. The sensor material is based on palladium(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorphenyl)-porphyrin embedded...

  17. Evaluation of micronuclei in mice bone marrow and antioxidant systems in erythrocytes exposed to α-amanitin.

    Science.gov (United States)

    Marciniak, B; Lopaczyńska, D; Kowalczyk, E; Skośkiewicz, J; Witczak, M; Majczyk, M; Grabowicz, W; Ferenc, T

    2013-03-01

    α-Amanitin, the main toxic substance from mushroom species (Amanita genus), blocks the activity of RNA polymerase II (Pol II) in mammalian cells causing inhibition of transcription and subsequent synthesis of structural and enzymatic proteins. It has been postulated that α-amanitin generates the increase of reactive oxygen species (ROS) concentration. The micronucleus (MN) test was used on an animal experimental model to evaluate possible potential genotoxic effect of α-amanitin on mice bone marrow cells. At the same time the activity of antioxidant enzymes: superoxide dismutase (SOD) and catalase (CAT) as well as concentration of thiobarbituric acid reactive substance (TBARS) were investigated in the lysate of mice erythrocytes. α-Amanitin was administered intraperitoneally at the doses: 0.1, 0.15, and 0.25 mg/kg bw (LD(50) for mice) 48 h prior to sacrification. A statistically significant increase of SOD activity was observed in the hemolysate for all the investigated α-amanitin doses as compared to the negative control (p activity for α-amanitin doses 0.1 and 0.15 mg/kg was higher in comparison to the negative control but the differences were not statistically significant (p > 0.05). However, for the dose 0.25 mg/kg the activity of CAT was statistically significantly higher (p  0.05). A statistically significant increase of mean values of MN percent was found in polychromatic erythrocytes (PCEs) as compared to the negative control for α-amanitin dose 0.1 and 0.25 mg/kg (p  0.1). The observed disturbances in the activity of the examined antioxidant enzymes in cells exposed in vivo to α-amanitin suggest indirect genotoxic effect of α-amanitin through ROS generation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Mercury chloride-induced oxidative stress in human erythrocytes ...

    African Journals Online (AJOL)

    ONOS

    2010-01-25

    Jan 25, 2010 ... ... role in the protection of cell membranes aganist oxidative damage .... Differences were calculated using one way analysis of variance (ANOVA) .... via the formation of reactive oxygen species and the perturbation of ...

  19. Microfabricated Chemical Sensors for Safety and Emission Control Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Chen, L.-Y.; Knight, D.; Liu, C. C.; Wu, Q. H.

    1998-01-01

    Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication (MicroElectroMechanical Systems (MEMS)-based) technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  20. Rubidium contents in erythrocyte of children, rice and soil in the areas with different selenium status

    International Nuclear Information System (INIS)

    Liu Nianqing; Zhao Shunying; Qian Qinfang; Zhu Lianzhen; Piao Jianhua

    1997-01-01

    Rubidium concentration of erythrocyte of healthy children aged from 6-11 years living in four areas of Sichuan Province with different selenium status was measured by PIXE and the results show that the Rb concentration in erythrocyte for the Keshan Disease area is two times more than other three areas. Meanwhile the glutathione peroxidase (GSHPx) activity of erythrocyte was determined and the results confirm that children in the Keshan Disease area are really with selenium deficiency. The Rb contents in rice and soil samples from the Keshan Disease area and the Se-deficiency area but with Se-supplementation to the inhabitants, were tested by INNA. It was found that Rb contents in rice and soil from the former area were much higher than those from the latter. This result indicates that Rb in erythrocyte of children is mainly taken from staple food (rice) and that a higher Rb level in soil is probably another environmental factor causing the Keshan Disease

  1. Recruitment of human aquaporin 3 to internal membranes in the Plasmodium falciparum infected erythrocyte.

    Science.gov (United States)

    Bietz, Sven; Montilla, Irine; Külzer, Simone; Przyborski, Jude M; Lingelbach, Klaus

    2009-09-01

    The molecular mechanisms underlying the formation of the parasitophorous vacuolar membrane in Plasmodium falciparum infected erythrocytes are incompletely understood, and the protein composition of this membrane is still enigmatic. Although the differentiated mammalian erythrocyte lacks the machinery required for endocytosis, some reports have described a localisation of host cell membrane proteins at the parasitophorous vacuolar membrane. Aquaporin 3 is an abundant plasma membrane protein of various cells, including mammalian erythrocytes where it is found in distinct oligomeric states. Here we show that human aquaporin 3 is internalized into infected erythrocytes, presumably during or soon after invasion. It is integrated into the PVM where it is organized in novel oligomeric states which are not found in non-infected cells.

  2. Erythrocytic Adenosine Monophosphate as an Alternative Purine Source in Plasmodium falciparum*

    Science.gov (United States)

    Cassera, María B.; Hazleton, Keith Z.; Riegelhaupt, Paul M.; Merino, Emilio F.; Luo, Minkui; Akabas, Myles H.; Schramm, Vern L.

    2008-01-01

    Plasmodium falciparum is a purine auxotroph, salvaging purines from erythrocytes for synthesis of RNA and DNA. Hypoxanthine is the key precursor for purine metabolism in Plasmodium. Inhibition of hypoxanthine-forming reactions in both erythrocytes and parasites is lethal to cultured P. falciparum. We observed that high concentrations of adenosine can rescue cultured parasites from purine nucleoside phosphorylase and adenosine deaminase blockade but not when erythrocyte adenosine kinase is also inhibited. P. falciparum lacks adenosine kinase but can salvage AMP synthesized in the erythrocyte cytoplasm to provide purines when both human and Plasmodium purine nucleoside phosphorylases and adenosine deaminases are inhibited. Transport studies in Xenopus laevis oocytes expressing the P. falciparum nucleoside transporter PfNT1 established that this transporter does not transport AMP. These metabolic patterns establish the existence of a novel nucleoside monophosphate transport pathway in P. falciparum. PMID:18799466

  3. Adhesion of Plasmodium falciparum infected erythrocytes in ex vivo perfused placental tissue

    DEFF Research Database (Denmark)

    Pehrson, Caroline; Mathiesen, Line; Heno, Kristine K

    2016-01-01

    placental tissue. RESULTS: The ex vivo placental perfusion model was modified to study adhesion of infected erythrocytes binding to CSA, endothelial protein C receptor (EPCR) or a transgenic parasite where P. falciparum erythrocyte membrane protein 1 expression had been shut down. Infected erythrocytes......, such as binding to immunoglobulins. Furthermore, other parasite antigens have been associated with placental malaria. These findings have important implications for placental malaria vaccine design. The objective of this study was to adapt and describe a biologically relevant model of parasite adhesion in intact...... expressing VAR2CSA accumulated in perfused placental tissue whereas the EPCR binding and the transgenic parasite did not. Soluble CSA and antibodies specific against VAR2CSA inhibited binding of infected erythrocytes. CONCLUSION: The ex vivo model provides a novel way of studying receptor-ligand interactions...

  4. Loading of erythrocyte membrane with pentacyclic triterpenes inhibits Plasmodium falciparum invasion

    DEFF Research Database (Denmark)

    Ziegler, Hanne L; Staalsø, Trine; Jaroszewski, Jerzy W

    2006-01-01

    Lupeol and betulinic acid inhibit the proliferation of Plasmodium falciparum parasites by inhibition of the invasion of merozoites into erythrocytes. This conclusion is based on experiments employing parasite cultures synchronized by magnetic cell sorting (MACS). Identical inhibitory effects were...

  5. Erythrocytes in muscular dystrophy. Investigation with 31P nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

    1981-01-01

    Phosphorus 31 nuclear magnetic resonance ( 31 P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual 31 P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which leads to lower steady-state concentrations of the intracellular phosphates

  6. Erythrocytes in muscular dystrophy. Investigation with 31P nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

    1981-01-01

    Phosphorus 31 nuclear magnetic resonance (31P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual 31P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which lead to lower steady-state concentrations of the intracellular phosphates

  7. Effect of complete protein 4.1R deficiency on ion transport properties of murine erythrocytes

    International Nuclear Information System (INIS)

    Rivera, Alicia; De Franceschi, Lucia; Peters, Luanne L.; Gascard, Philippe; Mohandas, Narla; Brugnara, Carlo

    2006-01-01

    Moderate hemolytic anemia, abnormal erythrocyte morphology (spherocytosis), and decreased membrane stability are observed in mice with complete deficiency of all erythroid protein 4.1 protein isoforms (4.1-/-; Shi TS et al., J. Clin. Invest. 103:331,1999). We have examined the effects of erythroid protein 4.1 (4.1R) deficiency on erythrocyte cation transport and volume regulation. 4.1-/- mice exhibited erythrocyte dehydration that was associated with reduced cellular K and increased Na content. Increased Na permeability was observed in these mice, mostly mediated by Na/H exchange with normal Na-K pump and Na-K-2Cl cotransport activities. The Na/H exchange of 4.1-/- erythrocytes was markedly activated by exposure to hypertonic conditions (18.2+- 3.2 in 4.1 -/- vs.9.8 +- 1.3 mmol/1013 cell x h in control mice), with an abnormal dependence on osmolarity, (K0.5=417 +- 42 in 4.1 -/- vs. 460 +- 35 mOsmin control mice) suggestive of an up-regulated functional state. While the affinity for internal protons was not altered (K0.5= 489.7 +- 0.7 vs.537.0 +- 0.56 nM in control mice), the Vmax of the H-induced Na/H exchange activity was markedly elevated in 4.1-/- erythrocytes Vmax 91.47 Moderate hemolytic anemia, abnormal erythrocyte morphology (spherocytosis), and decreased membrane stability are observed in mice with complete deficiency of all erythroid protein 4.1 protein isoforms (4.1-/-; Shi TSet al., J. Clin. Invest. 103:331,1999). We have examined the effects of erythroid protein 4.1 (4.1R) deficiency on erythrocyte cation transport and volume regulation. 4.1-/- mice exhibited erythrocyte dehydration that was associated with reduced cellular K and increased Na content. Increased Na permeability was observed in these mice, mostly mediated by Na/H exchange with normal Na-K pump and Na-K-2Cl cotransport activities. The Na/H exchange of 4.1-/- erythrocytes was markedly activated by exposure to hypertonic conditions (18.2 +- 3.2 in 4.1 -/- vs. 9.8 +- 1.3mmol/1013 cell x h in

  8. Magnetic measurements on human erythrocytes: Normal, beta thalassemia major, and sickle

    Science.gov (United States)

    Sakhnini, Lama

    2003-05-01

    In this article magnetic measurements were made on human erythrocytes at different hemoglobin states (normal and reduced hemoglobin). Different blood samples: normal, beta thalassemia major, and sickle were studied. Beta thalassemia major and sickle samples were taken from patients receiving lifelong blood transfusion treatment. All samples examined exhibited diamagnetic behavior. Beta thalassemia major and sickle samples showed higher diamagnetic susceptibilities than that for the normal, which was attributed to the increase of membrane to hemoglobin volume ratio of the abnormal cells. Magnetic measurements showed that the erythrocytes in the reduced state showed less diamagnetic response in comparison with erythrocytes in the normal state. Analysis of the paramagnetic component of magnetization curves gave an effective magnetic moment of μeff=7.6 μB per reduced hemoglobin molecule. The same procedure was applied to sickle and beta thalassemia major samples and values for μeff were found to be comparable to that of the normal erythrocytes.

  9. Spray drying for preservation of erythrocytes: effect of atomization on hemolysis.

    Science.gov (United States)

    McLean, Mary; Han, Xiao-Yue; Higgins, Adam Z

    2013-04-01

    Spray drying has the potential to enable storage of erythrocytes at room temperature in the dry state. The spray drying process involves atomization of a liquid into small droplets and drying of the droplets in a gas stream. In this short report, we focus on the atomization process. To decouple atomization from drying, erythrocyte suspensions were sprayed with a two-fluid atomizer nozzle using humid nitrogen as the atomizing gas. The median droplet size was less than 100 μm for all of the spray conditions investigated, indicating that the suspensions were successfully atomized. Hemolysis was significantly affected by the hematocrit of the erythrocyte suspension, the suspension flow rate, and the atomizing gas flow rate (pspray drying may be a feasible option for erythrocyte biopreservation.

  10. Influence of the use of statin on the stability of erythrocyte membranes in multiple sclerosis.

    Science.gov (United States)

    de Freitas, Mariana Vaini; de Oliveira, Marcela Ramos; dos Santos, Diogo Fernandes; de Cássia Mascarenhas Netto, Rita; Fenelon, Sheila Bernardino; Penha-Silva, Nilson

    2010-02-01

    Multiple sclerosis (MS) probably occurs by oxidative, inflammatory and autoimmune mechanisms. This study investigated the influence of statin on the stability of erythrocyte membranes in MS patients. The population was composed of one group with simvastatin therapy (20 mg/day), another group without statin therapy and a healthy control group. The stability of erythrocytes was evaluated by the half-transition points, H(50) and D(50), obtained from the curves of hemolysis induced by hypotonic shock and ethanol action, respectively. Erythrocytes of MS patients were less stable against lysis by both chaotropes. This behavior may be merely a consequence of the lifestyle of MS patients or it may be intrinsically associated with the conjunct of factors responsible for the development of the disease. The use of statin by MS patients was associated with lower levels of LDL and total cholesterol, as expected, and with higher stability of erythrocytes against ethanol compared to the values of untreated MS patients.

  11. Metabolism of tritiated D-glucose in rat erythrocytes

    International Nuclear Information System (INIS)

    Manuel y Keenoy, B.; Malaisse-Lagae, F.; Malaisse, W.J.

    1991-01-01

    The metabolism of D-[U-14C]glucose, D-[1-14C]glucose, D-[6-14C]glucose, D-[1-3H]glucose, D-[2-3H]glucose, D-[3-3H]glucose, D-[3,4-3H]glucose, D-[5-3H]glucose, and D-[6-3H]glucose was examined in rat erythrocytes. There was a fair agreement between the rate of 3HOH production from either D-[3-3H]glucose and D-[5-3H]glucose, the decrease in the 2,3-diphosphoglycerate pool, its fractional turnover rate, the production of 14C-labeled lactate from D-[U-14C]glucose, and the total lactate output. The generation of both 3HOH and tritiated acidic metabolites from D-[3,4-3H]glucose indicated incomplete detritiation of the C4 during interconversion of fructose-1,6-bisphosphate and triose phosphates. Erythrocytes unexpectedly generated 3HOH from D-[6-3H]glucose, a phenomenon possibly attributable to the detritiation of [3-3H]pyruvate in the reaction catalyzed by glutamate pyruvate transaminase. The production of 3HOH from D-[2-3H]glucose was lower than that from D-[5-3H]glucose, suggesting enzyme-to-enzyme tunneling of glycolytic intermediates in the hexokinase/phosphoglucoisomerase/phosphofructokinase sequence. The production of 3HOH from D-[1-3H]glucose largely exceeded that of 14CO2 from D-[1-14C]glucose, a situation tentatively ascribed to the generation of 3HOH in the phosphomannoisomerase reaction. It is further speculated that the adjustment in specific radioactivity of D-[1-3H]glucose-6-phosphate cannot simultaneously match the vastly different degrees of isotopic discrimination in velocity at the levels of the reactions catalyzed by either glucose-6-phosphate dehydrogenase or phosphoglucoisomerase. The interpretation of the present findings thus raises a number of questions, which are proposed as a scope for further investigations

  12. Respiratory adaptations in carp blood. Influences of hypoxia, red cell organic phosphates, divalent cations and CO2 on hemoglobin-oxygen affinity

    DEFF Research Database (Denmark)

    Weber, Roy E.; Lykkeboe, G.

    1978-01-01

    This study concerns the adaptation of oxygen transporting function of carp blood to environment hypoxia, tracing the roles played by erythrocytic cofactors, inorganic cations, carbon dioxide and hemoglobin multiplicity. Carp acclimated to hypoxia ( 30 mmHg) display striking increases in blood oxy...

  13. Dually Fluorescent Sensing of pH and Dissolved Oxygen Using a Membrane Made from Polymerizable Sensing Monomers

    OpenAIRE

    Tian, Yanqing; Shumway, Bradley R.; Youngbull, A. Cody; Li, Yongzhong; Jen, Alex K.-Y.; Johnson, Roger H.; Meldrum, Deirdre R.

    2010-01-01

    Using a thermal polymerization approach and polymerizable pH and oxygen sensing monomers with green and red emission spectra, respectively, new pH, oxygen, and their dual sensing membranes were prepared using poly(2-hydroxyethyl methacrylate)-co-poly(acrylamide) as a matrix. The sensors were grafted on acrylate-modified quartz glass and characterized under different pH values, oxygen concentrations, ion strengths, temperatures and cell culture media. The pH and oxygen sensors were excited usi...

  14. Inhibitin: a specific inhibitor of sodium/sodium exchange in erythrocytes.

    OpenAIRE

    Morgan, K; Brown, R C; Spurlock, G; Southgate, K; Mir, M A

    1986-01-01

    An inhibitor of ouabain-insensitive sodium/sodium exchange in erythrocytes has been isolated from leukemic promyelocytes. To explore the specific effects of this inhibitor, named inhibitin, sodium transport experiments were carried out in human erythrocytes. Inhibitin reduced ouabain-insensitive bidirectional sodium transport. It did not change net sodium fluxes, had no significant effect on rubidium influx, and did not inhibit sodium-potassium-ATPase activity. The inhibitory effect of inhibi...

  15. Oxidative Damage in Erythrocytes During Cold Storage With Organ Preservation Solution

    OpenAIRE

    MEMMEDOĞLU, Akif B.

    1999-01-01

    It is known that erythrocyte aggregation in renal tissue during preserva-tion is cause of microcirculation defects in the reperfusion period. The aim of our study is to investigate oxidative damage in erythrocytes relative to the time of cold ischemia during organ preservation and relationship between lipid peroxidation and development of these damages. In experiments with a rabbit model, explanted kidneys were exposed to perfusion and 96 hours preservation with Euro-Collins (EC) in the 1...

  16. The effect of exhaustive exercise on the concentration of purine nucleotides and their metabolites in erythrocytes

    OpenAIRE

    E Skotnicka; I Baranowska-Bosiacka; W Dudzińska; M Suska; R Nowak; K Krupecki; AJ Hłyńczak

    2008-01-01

    In this study we tried to obtain a complete overview of purine nucleotide metabolism in erythrocytes before and during an incremental, intermittent exhaustive exercise bout protocol for sportsmen (high-performance rowers) and untrained, healthy, active volunteers. Erythrocyte levels of the main nucleotides (ATP, ADP, AMP, GTP, GDP, GMP, IMP, NAD and NADP ), nucleosides (Ado, Guo, Ino) and the base Hyp were measured using the HPLC method. The parameters that can be deducted from their concent...

  17. Complement Receptor 1 Is a Sialic Acid-Independent Erythrocyte Receptor of Plasmodium falciparum

    Science.gov (United States)

    2010-06-17

    Sciences, Bethesda, MD, ...... 14. ABSTRACT Plasmodium falciparum is a highly lethal malaria parasite of humans. A major portion of its life cycle is...parasite of humans. A major portion of its life cycle is dedicated to invading and multiplying inside erythrocytes. The molecular mechanisms of...Complement Receptor 1 Is a Sialic Acid-Independent Erythrocyte Receptor of Plasmodium falciparum Carmenza Spadafora1,2,3, Gordon A. Awandare4

  18. Effects of copper, organic mercury and a mixture of the two on glycerol lysis of erythrocytes.

    OpenAIRE

    宮地,芳之

    1987-01-01

    The effects of copper, organic mercury and a mixture of the two on glycerol lysis of erythrocytes were examined. Copper ion and organic mercury (EMP; ethylmercury phosphate, and PCMB; sodium p-chloromercuricbenzoate) inhibited glycerol lysis of erythrocytes. The inhibitory effects was dependent on the incubation period. An equimolor solution of copper ion and EMP showed between copper ion and EMP. Similar results were obtained with copper and PCMB.

  19. Influence of Cocoa Flavanols and Procyanidins on Free Radical-induced Human Erythrocyte Hemolysis

    Directory of Open Access Journals (Sweden)

    Qin Yan Zhu

    2005-01-01

    Full Text Available Cocoa can be a rich source of antioxidants including the flavan-3-ols, epicatechin and catechin, and their oligomers (procyanidins. While these flavonoids have been reported to reduce the rate of free radical-induced erythrocyte hemolysis in experimental animal models, little is known about their effect on human erythrocyte hemolysis. The major objective of this work was to study the effect of a flavonoid-rich cocoa beverage on the resistance of human erythrocytes to oxidative stress. A second objective was to assess the effects of select purified cocoa flavonoids, epicatechin, catechin, the procyanidin Dimer B2 and one of its major metabolites, 3ʹ-O-methyl epicatechin, on free radical-induced erythrocyte hemolysis in vitro. Peripheral blood was obtained from 8 healthy subjects before and 1, 2, 4 and 8 h after consuming a flavonoid-rich cocoa beverage that provided 0.25 g/kg body weight (BW, 0.375 or 0.50 g/kg BW of cocoa. Plasma flavanol and dimer concentrations were determined for each subject. Erythrocyte hemolysis was evaluated using a controlled peroxidation reaction. Epicatechin, catechin, 3ʹ-O-methyl epicatechin and (--epicatechin-(4β > 8epicatechin (Dimer B2 were detected in the plasma within 1 h after the consumption of the beverage. The susceptibility of erythrocytes to hemolysis was reduced significantly following the consumption of the beverages. The duration of the lag time, which reflects the capacity of cells to buffer free radicals, was increased. Consistent with the above, the purified flavonoids, epicatechin, catechin, Dimer B2 and the metabolite 3ʹ-O-methyl epicatechin, exhibited dose-dependent protection against AAPH-induced erythrocyte hemolysis at concentrations ranging from 2.5 to 20 μM. Erythrocytes from subjects consuming flavonoid-rich cocoa show reduced susceptibility to free radical-induced hemolysis (p < 0.05.

  20. PIXE elemental analysis of erythrocyte and blood plasma samples from human pregnancies

    International Nuclear Information System (INIS)

    Borbely-Kiss, I.; Koltay, E.; Laszlo, S.; Szabo, Gy.

    1984-01-01

    Elemental concentrations of P, S, Cl, K, Ca, Fe, Ni, Cu, Zn, Br, Rb have been determined in erythrocyte and blood plasma samples from normal and diabetic human pregnancies. Average values, the dependence of the concentrations on the time during gestation period, the correlation coefficients for pairs of elements as well as for the same elements in plasma and erythrocyte samples are given. A marked difference appeared in a number of cases between normal and diabetic pregnancies. (author)