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PubMed2006

Distribution, structure, and dynamics of cesium and iodide ions at the H2O-CCl4 and H2O-vapor interfaces.

Molecular dynamics simulations utilizing many-body potentials of H2O-CCl4 and H2O-vapor interfaces were carried out at different cesium and iodide ion concentrations to compare ion distribution, interfacial orientational and structural properties, and dynamics. It was found that cesium was repelled by both interfaces, and iodide was active at both interfaces, but to a much greater degree at the H2O-vapor interface. At the interface, the iodide dipole was strongly induced, orienting perpendicular to the interface for both systems, leading to stronger hydrogen bonds with water. For the H2O-CCl4 interface, though, there was a compensation between these strong hydrogen bonds and short to moderate ranged repulsion between iodide and CCl4. Hydrogen bond distance and angular distributions showed weaker water-water hydrogen bonds at both interfaces, but generally stronger water-iodide hydrogen bonds. Both translational and rotational dynamics of water were faster at the interface, while for CCl4, its translational dynamics was slower, but rotational dynamics faster at the interface. For many of the studied systems and species, translational diffusion was found to be anisotropic at both interfacial and bulk regions.

Carbon↗
PubMed2001

Polymorphic ventricular tachycardia in a woman taking cesium chloride.

A 47-year-old patient presented with syncope and recurrent episodes of polymorphic ventricular tachycardia. She had evidence of prolonged QT interval by ECG and had been taking cesium as a dietary supplement. Correction of the hypokalemia and discontinuation of the cesium resulted in normalization of the QT interval during follow-up with no further recurrence of ventricular arrhythmias. The use of this drug is potentially hazardous as it may induce fatal ventricular arrhythmias.

Cesium↗
PubMed1955

The effects of sickling on ion transport. II. The effect of sickling on sodium and cesium transport.

When the red cells from patients with sickle cell anemia (S-S) were kept in the disk shape by incubation in O(2), they maintained cell sodium in the steady state for at least 10 hours. The sodium flux in such cells at 37 degrees C. was 6.0 +/- 1.5 m.eq./ (liters RBC) x (hours). When S-S cells were sickled by incubation in N(2), sodium outflux increased two- to threefold, while influx increased four- to fivefold and the cells gained net sodium. A small but undetermined fraction of the sodium in disk and sickle shaped S-S cells exchanges at one or more rates which are substantially slower than those calculated here from the initial rate of transfer of tracer from cells to the medium. The penetration of tracer Cs into normal and both disk and sickled S-S cells was markedly inhibited by increasing the K concentration in the medium, indicating that Cs and K compete for an entrance pathway in all three cell types. The ratio of the inward rate constant for tracer Cs to that for K(42) in normal and disk-shaped S-S cells increased only slightly when the K concentration in the medium was increased, indicating that almost all the Cs entered such cells in competition with K. Sickling accelerated the entrance of tracer cesium into S-S cells. Furthermore, the rate constant ratio increased with increasing external K concentration in sickled cells, suggesting the simultaneous presence of a non-competitive route for cesium influx in this cell type. The results are interpreted to support the view that sickling (a) accelerates inward transport of K and Cs and outward transport of Na by a non-diffusion, assumed carrier, process and (b) opens pathways for the diffusion of all three ions.

Anemia, Sickle Cell↗
PubMed1966

Voltage clamp studies on the effect of internal cesium ion on sodium and potassium currents in the squid giant axon.

Isolated and cleaned giant axons of Loligo pealii were internally perfused with solutions containing cesium sulfate and potassium fluoride. Membrane currents obtained as a function of clamped membrane potentials indicated a severe depression of the delayed outward current component normally attributed to potassium ion movement. Steady-state currents showed a negative slope in the potential range from -45 to -5 mv which corresponded to the negative slope for the peak sodium current relation vs. membrane potential which suggested long duration sodium currents. Using sodium-free sea water externally, sodium currents were separated from total currents and these persisted for longer times than normal. This result suggested that internal cesium ion delays the sodium conductance turnoff. The separated nonsodium currents showed an abnormal rectification as compared with those predicted by the independence principle, such that while potassium permeability appeared normal at the resting potential, its value decreased progressively with increasing depolarization.

Animals↗
PubMed1990

Rubidium and cesium as host blood-markers to study multiple blood feeding by mosquitoes (Diptera: Culicidae).

We have developed an experimental technique to quantify multiple blood feeding by mosquitoes during a single gonotrophic cycle on conspecific or closely related vertebrate hosts. Rubidium and cesium were detected in mosquitoes that fed on chickens injected with these elements 3 d earlier. Experimentally induced double blood meals were confirmed by the presence of both rubidium and cesium in individual mosquitoes. Multiple blood feeding by Culiseta melanura also was demonstrated in nature using this technique. This was the first simultaneous use of two alkali metals as host blood-markers for the study of mosquito blood-feeding behavior.

Aedes↗
PubMed1994

Cesium abolishes the barium-induced pacemaker potential and current in guinea pig ventricular myocytes.

INTRODUCTION: The ability of cesium to block barium-induced diastolic depolarization ("Ba-DD") and pacemaker current was tested in isolated ventricular myocytes. Because Ba-DD is due to decreasing K+ conductance and there is no I(f) at the resting potential, this approach permits verification of whether Cs+ is a specific blocker of i(f) or if it instead also blocks a K+ pacemaker current. METHODS AND RESULTS: Guinea pig isolated ventricular myocytes were studied by a discontinuous, single electrode, voltage clamp method. During hyperpolarizing voltage clamp steps from -80 up to -140 mV in Tyrode's solution, the inward current increased as a function of voltage but did not change as a function of time (no I(f) or K+ depletion). Cesium (4 mM) reduced the current size during the hyperpolarizing steps but did not induce or unmask time-dependent currents. Barium (0.05 to 0.1 mM) induced diastolic depolarization, and, in its presence, depolarizing voltage clamp steps were followed by an outward tail current that reversed at -92.0 +/- 1.3 mV. Outward tail currents were larger at -50 mV than at the resting potential, and inward tail currents decayed more rapidly and to a larger extent during larger hyperpolarizing steps. In the presence of Ba2+, Cs+ (4 mM) had little effect on the steady-state current but markedly reduced or abolished undershoot, Ba-DD, and time-dependent tail currents at potentials both positive and negative to the resting potential. Cs+ had a smaller effect on the steady-state current-voltage (I-V) relation in the presence than in the absence of Ba2+, as part of the IK1 channels were already blocked by Ba2+ and the time-dependent changes induced by Ba2+ were not present. Both Ba2+ and Cs+ had little blocking effect on the steady-state current positive to the negative slope region of the I-V relation. CONCLUSION: In ventricular myocytes, Cs+ abolishes the Ba(2+)-induced pacemaker current by blocking the time-dependent change in K+ conductance, not by blocking I(f). Because Cs+ can also block a decaying K+ pacemaker current, the abolition of a pacemaker current by Cs+ in other cardiac tissues cannot be taken as unequivocal proof that the blocked current is I(f).

Animals↗
PubMedDate not supplied

Experimental verification of cesium brachytherapy line source emission using a semiconductor detector.

Described is an experimental verification technique for cesium brachytherapy line source emission. The dose rate levels produced by a line source algorithm are compared with measurements taken around J-series stainless-steel sheathed cesium sources with a p-type semiconductor diode detector. Further study of isodensity contours is undertaken using a film dosimetry technique. The errors involved in using these techniques are assessed.

Algorithms↗
PubMed1966

Cesium-137 body burdens in Alaskan Eskimos during the summer of 1965.

Cesium-137 body burdens of Anaktuvuk Pass, Alaska, residents during the summer of 1965 were about 30 percent less than during 1964. Lower amounts of cesium-137 in the people reflected a similar decrease of this isotope in caribou flesh, which serves as the principal food of the natives.

Adolescent↗
PubMed1990

The interrelationship of cesium, intracellular sodium activity, and pacemaker potential in cardiac Purkinje fibers.

The actions of cesium (Cs) on intracellular sodium activity (aiNa), membrane potentials, and force were studied in sheep cardiac Purkinje and myocardial fibers superfused in vitro. In Purkinje fibers, Cs (2 mM) decreased diastolic depolarization, aiNa (-6.7%, p less than 0.005), and force (-28.0%, p less than 0.01). The effects of 4 and 8 mM Cs were more pronounced. In quiescent fibers, Cs (2-4 mM) also decreased aiNa (-17.3%, p less than 0.005) and induced an initial hyperpolarization (+5.6 +/- 1.3%, p less than 0.005) followed by a return toward control. Diastolic depolarization was almost abolished by driving the fibers at 180/min (diastole was very short) but still Cs decreased aiNa (-15.4%). Tetrodotoxin decreased aiNa (-16.2%, p less than 0.025) and reduced the Cs-induced fall in aiNa (-2.2%, p less than 0.05). In zero [K]o, Cs decreased aiNa and caused repolarization. In 0.1 mM strophanthidin, Cs did not decrease aiNa any longer and affected the membrane potential little. In quiescent myocardial fibers, Cs (4 mM) decreased aiNa (-12.6%, p less than 0.05) and transiently hyperpolarized (+2.1%). Rubidium (2 mM) decreased aiNa and resting potential in Purkinje fibers and in myocardial fibers and also decreased diastolic depolarization in Purkinje fibers. Thus, cesium and rubidium decrease aiNa and modify the membrane potential but not through a block of the inward pacemaker current If.

Animals↗
PubMed1997

Three-dimensional activation sequence of cesium-induced ventricular arrhythmias.

To investigate the electrophysiological and electrocardiographic characteristics of ventricular arrhythmia due to abnormal repolarization, we studied the three-dimensional activation sequence of cesium-induced ventricular tachycardia (VT) in 10 anesthetized dogs using a 384-channel recording system. Seventeen monomorphic VT (mVT) and eight polymorphic VT (pVT) episodes induced by cesium chloride (2 or 3 mM/kg) were analyzed. Only a single arrhythmogenic focus was detected in most beats of VT, whereas two competing foci were temporarily observed in two episodes of pVT. The site of arrhythmogenic focus of mVT was the endocardium (5 of 17), the midmyocardium (4 of 17), or undetermined (8 of 17). Both endocardial and midmyocardial arrhythmogenic foci were also found in pVT, and most pVT (6 of 8) were associated with the transition of the site of arrhythmogenic focus. These results are consistent with the view that both myocardial muscle fibers and Purkinje cells can cause ventricular arrhythmia due to abnormal repolarization and that changing the site of arrhythmogenic focus is the main mechanism of pVT.

Animals↗
PubMed1990

Alpha-adrenoceptor stimulation and blockade modulates cesium-induced early afterdepolarizations and ventricular tachyarrhythmias in dogs.

In 84 open-chest dogs, we studied the effects on early afterdepolarizations (EADs) and ventricular tachyarrhythmias (VTs) induced by cesium chloride (168 mg/kg i.v.) of alpha-adrenoceptor stimulation with phenylephrine (100 micrograms plus 0.25 microgram/kg/min i.v.) and with left ansa subclavia stimulation (LAS; 2 Hz, 4 msec, 2 mA) after propranolol (0.5 mg/kg) administration. We also studied the effects of alpha-adrenoceptor blockade with phentolamine (3 mg/kg), prazosin (25-500 micrograms/kg), yohimbine (10-500 micrograms/kg), WB 4101 (2 mg/kg), and benoxathian (2 mg/kg) during decentralized LAS. EAD amplitude, presented as a percentage of monophasic action potential amplitude, was recorded simultaneously with contact electrodes from the right and left ventricular endocardium. Phenylephrine and LAS plus propranolol increased EAD amplitude (31.5 +/- 8.8% to 47.8 +/- 9.7% and 34.8 +/- 4.1% to 46.1 +/- 6.4%, respectively) and the prevalence of VT (from three to nine of 11 dogs and from the three to five of six dogs, respectively). Prazosin produced a dose-response decrease in EAD amplitude and reduced the prevalence of VT. Yohimbine did not alter the amplitude of EADs or the prevalence of VT. WB 4101 and phentolamine reduced the amplitude of EADs produced by cesium and LAS (from 44.3 +/- 10.2% to 32.6 +/- 9.4% and from 39.8 +/- 6.9% to 30.3 +/- 6.3%, respectively) and the prevalence of VT (from eight to one of 10 dogs and from 13 to 5 of 20 dogs, respectively). Benoxathian did not alter significantly the amplitude of EADs (41.6 +/- 11.4% to 37.5 +/- 9.4%) or the prevalence of VT (from six to five of 10 dogs).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Cesium determination in physiological fluids and tissues by field desorption mass spectrometry.

Quantitative ultratrace analysis (10 nmol to 10 mumol/l) of cesium in biological samples such as human body fluids and animal tissues is performed without any prior purification or concentration steps. The normal level of cesium ions in heart cells was determined. After poisoning these cells with high concentrations of the alkali cation much higher levels were found inside the cells then had been suggested previously. It is demonstrated that field desorption mass spectrometry is a unique tool for the qualitative and quantitative investigations of metal cations in biological material.

Cesium↗
PubMed2002

Activity of rubidium and cesium in soybean looper (Lepidoptera: Noctuidae): insect feeding on cotton and soybean measured by elemental markers.

Uptake and translocation of the elemental markers rubidium (Rb) and cesium (Cs) within adult soybean looper, Pseudoplusia includens (Walker), were determined using atomic absorption spectrophotometry in the laboratory in various feeding and mating treatments. Neonates were tested to determine marker transfer from male and female adults fed rubidium chloride (RbCl)-treated artificial nectar, cesium chloride (CsCI)-treated artificial nectar, or both. All females contained detectable levels of Rb, Cs, or both, which were obtained either through direct feeding or via spermatophores. Rubidium was present in females at significantly greater levels than Cs. No significant differences in Rb levels were observed between feeding or spermatophore acquisitions. Most neonates had significantly higher levels of Rb than Cs. In a field cage study to evaluate adult feeding and oviposition behavior on blooming cotton and blooming soybean treated with RbCl and CsCl, respectively, more eggs contained Rb than Cs, indicating greater feeding on cotton nectar than soybean nectar, regardless of the host plant upon which eggs were laid. Females laid more eggs on blooming soybean than on blooming cotton. Higher levels of Rb in cotton than Cs in soybean were recorded and may be attributed to initial elemental marker quantities available to the insects. This study provides the support for the generalized observations that soybean looper infestations in soybean can be related to feeding activities by adults in cotton.

Animals↗
PubMedDate not supplied

Immobilization of cesium-137 and uranium in contaminated sediments using soil amendments.

Batch and dynamic leaching methods were used to evaluate the effectiveness of hydroxyapatite (HA), illite, and zeolite, alone and in combination, as soil additives for reducing the migration of cesium-137 (137Cs+) and uranium (U) from contaminated sediments. Amendment treatments ranging from 0 to 50 g kg(-1) were added to the sediment and equilibrated in 0.001 M CaCl2. After equilibration, the treatment supernatants were analyzed for 137Cs+, U, PO4, and other metals. The residual sediments were then extracted overnight using one of the following: 1.0 M NH4Cl, 0.5 M CaCl2, or the Toxicity Characteristic Leaching Procedure (TCLP) extractant. Cesium was strongly sorbed to the contaminated sediments, presumably due to interlayer fixation within native illitic clays. In fact, 137Cs+ was below detection limits in the initial equilibration solutions, the CaCl2 extract, and the TCLP solution, regardless of amendment. Extractants selective for interlayer cations (1.0 M NH4Cl) were necessary to extract measurable levels of 137Cs+. Addition of illitic clays further reduced Cs+ extractability, even when subjected to the aggressive extractants. Zeolite, however, was ineffective in reducing Cs+ mobility when subjected to the aggressive extractants. Hydroxyapatite was less effective than illite at reducing NH4+-extractable Cs+. Hydroxyapatite, and mixtures of HA with illite or zeolite, were highly effective in reducing U extractability in both batch and leaching tests. Uranium immobilization by HA was rapid with similar final U concentrations observed for equilibration times ranging from 1 h to 30 d. The current results demonstrate the effectiveness of soil amendments in reducing the mobility of U and Cs+, which makes in-place immobilization an effective remediation alternative.

Cesium Radioisotopes↗
PubMedDate not supplied

Cesium-134 as a tracer to study particle transport processes within a small catchment with a buffer zone.

The purpose of the study is to use soil particles labeled with the radioactive tracer cesium-134 (134Cs) as a method for studying soil erosion and sedimentation pattern within a small catchment with buffer zones. Cesium is adsorbed to soil particles, and by measuring changes in the 134Cs activity on the soil surface, erosion, sedimentation, and pathways for particles can be traced. A harrowed area was surface-contaminated with 134CsCl, while the buffer zone was left uncontaminated. A grid net in the tilled plot and buffer zone was established for in situ measurements of the 134Cs activity after major runoff events from October 1993 to May 1996. In addition, 134Cs activity and suspended solids in runoff were followed during the events. At the end of the experiment, the vertical distribution of 134Cs in soil profiles and uptake of 134Cs in vegetation within the buffer zone were determined. At the end of the experiment, about 54% of the applied tracer remained at the soil surface. Surface soil erosion occurred relatively uniformly across the hillslope due to sheet flow. Most of the tracer was transported vertically into the soil profile, probably during the first heavy rainfall 3 wk after application when the soil was newly tilled. Sedimentation occurred in the upper part of the buffer zone. The correlation between suspended particles in runoff and 134Cs activity was good (R2=0.76). The study also demonstrates the benefit of utilizing 134Cs2+ tracer for investigating transport pathways for contaminated partic1les within a hillslope system without disturbing the surface soil system.

Cesium Radioisotopes↗
PubMed1987

Radioactive iodine and cesium in travellers to different parts of Europe after the Chernobyl accident.

Thyroid uptake of 131I was measured in 130 volunteers following the nuclear power plant accident at Chernobyl in April 1986. Ninety of these volunteers had been travelling in different parts of eastern Europe at the time of or immediately after the accident while 40 persons were permanently in Sweden. Also, 28 additional healthy volunteers, living in Sweden, were chosen for a long-term follow-up of the time-course of 134Cs and 137Cs whole body uptake. The highest levels of 131I were found in persons having visited Poland (mean value 3.27 kBq +/- 3.68 SD, extrapolated to April 27) while persons that had stayed in other parts of eastern or northern Europe showed significantly lower levels (p less than 0.01). The whole body burdens of cesium radionuclides were barely detectable immediately after the accident but increased gradually throughout the observed period. After five months nine farmers from a high fallout area in central Sweden had reached mean values of 4.20 kBq (+/- 3.34 SD) of 134Cs and 137Cs while six nonfarmers from the Stockholm area showed significantly lower levels, 0.64 kBq (+/- 0.24 SD, p less than 0.05). The radiation doses from the observed amounts of iodine and cesium isotopes reported in this study reflect only a marginal addition to the already existing dose from the natural environmental background radiation.

Accidents↗
PubMedDate not supplied

[Food fibers--blockers and decontaminants of the radionuclides cesium and strontium].

The Chernobyl accident and its resultant radioactive pollution of enormous areas led to long-term entrance of radionuclides into the human habitat. Among more than 200 radionuclides, the products of uranium fission in the reactor of the atomic power station, the isotopes of iodine, cesium, and strontium present the highest hazard. If iodine-131 virtually decayed by August, 1986, the long-lived isotopes of cesium and strontium will still stir the world public and scientists for many years. The authors' result show that new types of dietary cellulose and composite food additives based on alfalfa polymers have rather pronounced antiradioactive properties against Cs-137 and Sr-85. This makes it necessary to organize the manufacture of these food additives whose daily dose of 12-20 should be supplemented into human diet every day.

Animals↗
PubMed1992

Radioactive cesium in dirt accumulations on the roof of buildings.

The concentrations of 137Cs and 134Cs in dirt deposits on the roofs of buildings are much higher than those in the surface of soil at ground level. Thus dirt on roofs concentrates radioactive cesium in fall-outs. The 137Cs concentration in dirt deposits on the roofs of older buildings is not consistently higher than that on the roofs of new ones, but the 137Cs/134Cs ratio is higher in deposits on older buildings constructed before the first half of the 1970s, and decreases exponentially with decrease in age of the buildings gradually reaching 1.9 +/- 0.2, the value in the air-borne dust at the time of the Chernobyl accident. From this relationship, the contribution of Chernobyl radioactivity to accumulated 137Cs was calculated as 32% on buildings constructed in 1962. The radioactive cesium concentrations in dirt deposits in gutters of private houses and on the roofs of university buildings in Japan were also determined.

Air Pollutants↗