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At least 109 records · Page 6Linked to original sources
PubMed1990

Intracellular cesium separates two glutamate conductances in retinal bipolar cells of goldfish.

The responses of depolarizing bipolar cells to glutamate were investigated in the superfused isolated goldfish retina. In intracellular recordings with potassium-filled microelectrodes, glutamate hyperpolarized cells but did not alter the net input conductance. In recordings with cesium-filled microelectrodes, the glutamate-evoked hyperpolarization was associated with a net conductance decrease. In the presence of internal cesium, glutamate action had the same reversal potential as the actions of the glutamate analog 2-amino-4-phosphonobutyrate (APB) and the rod transmitter, suggesting that all three of these substances act at the same class of receptor. We propose that glutamate acts both at the APB-sensitive receptor that mediates rod inputs and at another receptor type that produces a conductance increase, is blocked by cesium, and may mimic the action of the cone transmitter.

Aminobutyrates↗
PubMed1991

Transfer of Chernobyl fallout radionuclides from feed to growing rabbits: cesium-137 balance.

Intake, excretion and retention of gamma-emitting radionuclides were assessed in male rabbits fed a radioactive pelleted diet (137Cs = 858 Bq kg-1 as fed) containing 40% dehydrated alfalfa meal contaminated by Chernobyl fallout. In order to evaluate radionuclide retention, an experiment was carried out on 33 animals as follows: nine rabbits were slaughtered at the beginning of the trial, six were fed a radioactive diet for 42 days, six a radioactive diet for 21 days, six a radioactive diet for 21 days and a normal diet (137Cs = 112 Bq kg-1 as fed) for the following 21 days and six a normal diet for 42 days. All the animals were housed in individual metabolism cages throughout the trial. All faeces and urine were collected and analyzed separately and live weight and feed intake were measured on a weekly basis. At the end of the trial all the animals were slaughtered and the activities of net body and muscles were determined. Cesium-137, 134Cs, 103Ru, 106Ru, 125Sb, 110mAg and 40K were measured by gamma spectroscopy. More than 85% of ingested cesium was excreted through faeces and urine (fecal much greater than urinary) and the retained 137Cs in the carcass of the more contaminated animals was only 3% of the total ingested. The concentration of total cesium in muscle reached a maximum value of 156 Bq kg-1, much lower than the EEC guideline (600 Bq kg-1), and the biological half-life for 137Cs was calculated to be 11 days. The feed-body accumulation factors were determined in net body and muscle.

Accidents↗
PubMed1993

Levels of cesium-137 in seawater and fish from the Brazilian coast.

Considering environmental pollution problems and their impact on man, we have developed a research programme on environment monitoring. The aim of this work was to develop and to apply radiochemical methods for the analysis of cesium-137 in marine samples, such as seawater and fish. Cesium-137 levels in surface seawater from the coastal region of São Paulo State range from 1.7 to 1.9 Bq.m-3. Samples of the five species of fish most consumed by local population were taken for the analysis of cesium-137. Levels for fish varied from 0.1 to 0.3 Bq.kg-1 of edible part. Data were used to calculate dose assessment.

Animals↗
PubMed1985

Stage I carcinoma of the endometrium: a 5-year experience utilizing preoperative cesium.

A treatment protocol for the management of stage I endometrial carcinoma utilizing preoperative cesium is evaluated. One hundred and twelve consecutive patients were treated according to this protocol over a 5-year period. Based on this experience and a literature review a new protocol is recommended. The significant changes include primary surgery without preoperative cesium, primary treatment based on grade without regard to uterine size, modified radical hysterectomy for G3 tumors, pelvic radiotherapy for clear cell carcinoma confined to the pelvis regardless of depth of invasion, cytoxan, adriamycin, and cis-platinum for papillary serous tumors, and postoperative vaginal cuff cesium for G2 and G3 tumors not requiring pelvic radiotherapy.

Adenocarcinoma↗
PubMed1984

Effect of oral intake of cesium chloride: a single case report.

The author volunteered to experience on himself the effect of short-term, i.e., 36 consecutive days, oral administration of cesium chloride. Cesium chloride was given 6 g per day into two equally divided doses. The drug was dissolved in 8 ounces fluid and consumed immediately after the morning and evening meals which were diet-restricted to wheat bran and certain grain products, to attain approximately 1% potassium intake, for the initial 3 weeks. Bread products were discontinued and yogurt and cottage cheese products were reinstituted for the two week period that followed prior to reinstituting of the preceding food regimens. There was an initial general feeling of well-being and heightened sense perception. A gradual decrease in appetite was noted initially before it was stabilized at a later date. Discontinuation of rich bread meals resulted in pre-nausea sensation which was followed by diarrhea 48 hr later. The institution of high potassium nutrition decreased the feeling of nausea and abolished diarrhea. A "tingling" sensation in the lip and cheek regions was experienced 15 min subsequent the cesium chloride dosage compared to same sensation occurring at moderate intensity in hands and feet at end of the experiment. No adverse effects of CsCl were noted in performance of mathematical analyses or in driving skill. It is concluded that CsCl is devoid from toxicity provided adequate diet and supplements are administered.

Administration, Oral↗
PubMed1983

Cesium attenuates conditioned avoidance response in rats and mice.

The pole-climbing conditioned avoidance response (CAR) was attenuated in rats after four once-daily injections of CsCl intraperitoneally at 3.0 mEq kg-1 and in mice after seven such injections at 5.0 mEq kg-1. Suppression of CAR increased with increasing numbers of injections. Treatment with cesium did not attenuate the unconditioned pole-climbing escape response to mild footshock. The cesium effect on CAR resembles that of antidopaminergic phenothiazine like agents, in concordance with our earlier studies which showed cesium potentiation of pentobarbital sleeping time and antagonism of amphetamine toxicity.

Animals↗
PubMed2000

Beneficial effect of cesium salts on Pd-catalyzed hydroxycarbonylation.

A Pd(0)-catalyzed hydroxycarbonylation of the aryl bromide was effectively carried out in the presence of some Cs salts such as cesium carbonate, cesium bicarbonate, and cesium acetate in wet DMF solution. For the understanding of their function, an oxy-coordinated intermediate arising from a Cs oxygen-Pd interaction has been postulated, which is likely to be responsible for related Cs assisted catalytic processes.

Bromides↗
PubMed2003

Novel polymeric chelating fibers for selective removal of mercury and cesium from water.

We report here the synthesis and characterization of two new classes of chelating fibers, namely, (1) polymercaptopropylsilsesquioxane (PMPS) and (2) copper(II) ferrocyanide complexed with poly[1-(2-aminoethyl)-3-aminopropyl]silsesquioxane (Cu-FC-PAEAPS) fibers. These fibers were evaluated for selective removal of trace amount of mercury and cesium ions respectively in the presence of competing metal ions from water. The PMPS and Cu-FC-PAEAPS fibers were prepared by coating their corresponding soluble prepolymers, which are derived from mercaptopropyltrimethoxysilane and [1-(2-aminoethyl)-3-aminopropyl]trimethoxysilane monomers, respectively, on a glass fiber substrate, followed by a cross-linking step at 120 degrees C. The fibers were characterized through infrared spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). These novel materials are extremely efficient in removing low concentrations of mercury and cesium ions from water in the presence of high concentrations of sodium or potassium ions. They were shown to remove trace mercury and cesium contaminants effectively to well below parts per billion concentrations under a variety of conditions.

Cesium↗
PubMed1971

Control by cesium and intermediates of the citric acid cycle of extracellular ribonuclease and other enzymes involved in the assimilation of nitrogen.

Synthesis of extracellular ribonuclease is induced in cell cultures of Ustilago sphaerogena that are starved for nitrogen and exposed to the gratuitous inducer, 6-mercaptopurine. Cesium, ammonium, or alkylammonium ion represses ribonuclease induction. Addition of citric-acid cycle intermediates to cesium ionrepressed cultures partially restores the rate of ribonuclease synthesis to the induced level. Enzymes involved in assimilation of nitrogen from different sources are also repressed by cesium ion and derepressed by intermediates from the citric acid cycle.

Ammonia↗
PubMed1994

Transport of iodine and cesium via the grass-cow-milk pathway after the Chernobyl accident.

More than 150 data sets giving time-dependent concentrations of 131I and 137Cs in feed and milk of cows after the Chernobyl accident are evaluated using a minimal compartmental modeling approach. Transfer of cesium via the grass-cow-milk pathway is adequately described by a three-compartmental model. No unique model results for 131I, as a compartment with slow secretion of 131I into milk, are identified for some datasets only. Frequency distributions of weathering half-lives on grass and of equilibrium feed-to-milk transfer coefficients are approximately lognormal. Mean values of weathering half-lives on plants are 9.1 +/- 0.6 d for iodine and 11.1 +/- 0.8 d for cesium, in good agreement with means established from experiments performed before 1986. Mean values of equilibrium feed-to-milk transfer coefficients are 3.4 +/- 0.4 10(-3) d L-1 for 131I and 5.4 +/- 0.5 10(-3) d L-1 for 137 Cs. Both are lower than means calculated from the pre-Chernobyl data base. Plausible explanations of the differences include (1) reduced availability of fallout compared to soluble tracer; (2) underestimation of post-Chernobyl transfer coefficients by some experiments concluded too early to record slow transport processes; and (3) reduced transfer of 131I compared to long-lived iodine isotopes due to decay during fixation in the thyroid. Feed-to-milk transfer of 131I is related to milk yield, but no influence of milk yield and type of feed on transfer is apparent for cesium.

Accidents↗
PubMed2004

Contents of cesium, iodine, strontium, thorium, and uranium in selected human organs of adult asian population.

Contents of cesium, iodine, strontium, thorium, and uranium in some selected human organs were estimated for adult Asian population using data obtained in four Asian countries: China, India, Philippines, and Republic of Korea, as part of a Coordinated Research Program of the International Atomic Energy Agency on "Ingestion and Organ contents of elements of importance in radiation protection." These countries together represent more than 40% of the world population. Highly sensitive analytical techniques were employed to measure cesium in skeletal muscle, iodine in thyroid, strontium in skeleton, thorium and uranium in skeleton, liver, kidneys, and lungs where, in comparison to other organs, these elements are present in higher concentrations. The organ contents for adult Asian population, when compared with the corresponding data proposed for Reference Man by International Commission on Radiological Protection (ICRP), showed about 40 times lower kidneys content and about 10 times lower skeleton content of uranium. The content of thorium in skeleton for Asian population was also half of the ICRP Reference Man value. Interestingly, organ contents for the other elements such as iodine in thyroid, cesium in skeletal muscle, and strontium in skeleton were comparable for Asian and the Caucasian population (represented by ICRP Reference Man). Organ contents for these elements were also calculated by applying the new ICRP models of these elements to their daily intakes. The comparison of the calculated and measured organ contents showed that despite uncertainties in the organ content values arising due to the inter-country variations in daily dietary intakes, the contents were within a factor of two to three. This observation is significant since human data both on organ contents and ingestion were obtained at environmental level of intakes. The study suggests that currently available ICRP models for these elements are quite realistic.

Adult↗
PubMed1987

Radioactive cesium from the Chernobyl accident in the Greenland Ice Sheet.

Measurements of cesium-134 and cesium-137 in Greenland snow together with models of long-range transport have been used to assess radionuclide deposition in the Arctic after the Chernobyl accident. The results suggest that a well-defined layer of radioactive cesium is now present in polar glaciers, providing a new reference for estimating snow accumulation rates and dating ice core samples.

Accidents↗
PubMed2000

Simulated bone erosions in a hand phantom: detection with conventional screen-film technology versus cesium iodide-amorphous silicon flat-panel detector.

PURPOSE: To assess the diagnostic performance of an active-matrix flat-panel x-ray detector for reduced-dose imaging of simulated arthritic lesions. MATERIALS AND METHODS: A digital x-ray detector based on cesium iodide and amorphous silicon technology with a panel size of 43 x 43 cm, matrix of 3,000 x 3,000 pixels, pixel size of 143 micrometer, and digital output of 14 bits was used. State-of-the-art screen-film radiographs were compared with digital images obtained at doses equivalent to those obtained with system speeds of 400, 560, and 800. The phantom was composed of a human hand skeleton on an acrylic plate with drilled holes simulating bone erosions of different diameters and depths. Results of four independent observers were evaluated with receiver operating characteristic curve analysis. RESULTS: The cesium iodide and amorphous silicon detector resulted in better diagnostic performance than did the screen-film combination, with the dose being the same for both modalities (P <.05). For digital images obtained at reduced doses, no significant differences were found. CONCLUSION: The improved diagnostic performance with digital radiographs obtained with the cesium iodide and amorphous silicon detector suggests that this detector technology holds promise in terms of dose reduction for specific diagnostic tasks, without loss of diagnostic accuracy.

Arthritis↗
PubMed1997

Effects of ionic channel antagonists barium, cesium, and UL-FS-49 on vagal slowing of atrial rate in dogs.

In response to a brief vagal stimulus, the atrial rate initially slows, then transiently accelerates, and slows a second time. We determined the effects of three antagonists to two ionic channels on this characteristic triphasic pacemaker response. Brief bursts of vagal stimulation were delivered to anesthetized dogs, and atrial cycle lengths were recorded. Either barium, cesium, or UL-FS-49 was administered. Barium, which primarily blocks the acetylcholine-sensitive potassium current (IK,ACh), attenuated the initial vagally induced bradycardia by > 50% without affecting the subsequent acceleration or the secondary slowing. Cesium and UL-FS-49 [both of which primarily block the pacemaker current (If)] did not affect the initial vagal slowing of atrial rate but abolished the acceleratory portion of the response. The secondary slowing was abolished by cesium but not by UL-FS-49. We conclude that the initial rapid atrial response to acetylcholine is mediated mainly by the IK,ACh, with little contribution from the If. The subsequent acceleration is mediated by activation of the If.

Acetylcholine↗
PubMed1988

Autonomic modulation of ventricular arrhythmia in cesium chloride-induced long QT syndrome.

To evaluate autonomic influence on arrhythmogenesis in an animal preparation of triggered activity, we gave increasing doses of cesium chloride (0.125 to 5.0 mmol/kg iv) to 24 dogs distributed equally among four protocols of autonomic intervention: control, total denervation, beta-blockade, and left stellate stimulation. All dogs underwent atrioventricular node ablation followed by ventricular pacing. A left ventricular endocardial monophasic action potential (MAP) catheter allowed for detection of "MAP early afterdepolarizations" (mEAD). mEAD amplitude was measured relative to MAP amplitude. Cesium chloride (CsCl) increased both MAP duration (132% after 0.125 mmol/kg to 188% after 1.0 mmol/kg; p less than .001) and mEAD amplitude (20% after 0.125 mmol/kg to 49% after 1.0 mmol/kg; p less than .001) in a dose-dependent fashion. All dogs exhibited ventricular ectopy at roughly equivalent doses (0.88 +/- 0.5 mmol/kg). Cesium's peak effect on MAP characteristics, sinus node automaticity, and systolic blood pressure coincided with the onset of sustained ventricular tachycardia (VT). Whereas control and denervated dogs developed VT after similar doses of CsCl (1.21 +/- 0.1 vs 1.12 +/- 0.14 mmol/kg; p = NS), none of the six beta-blocked dogs developed sustained VT. Conversely, those dogs having undergone stellate stimulation developed VT after smaller doses (0.58 +/- 0.34 mmol/kg; p less than .001) and with earlier onset (12 vs 30 sec; p less than .025). After 0.5 mmol/kg of CsCl, left stellate stimulation augmented relative mEAD amplitude compared with control (51% vs 38%; p less than .001), whereas beta-blockade had little effect (39% vs 38%; p = NS). Autonomic intervention as such can affect the arrhythmogenicity of CsCl and similarly alter MAP characteristics. Furthermore, as beta-blockade can prevent sustained arrhythmia without eliminating mEADs, autonomic tone appears to modulate the expression of mEADs as sustained VT.

Action Potentials↗
PubMed1992

[Effects of magnesium on early post-depolarization and trigger activity induced by cesium on Purkinje fibers in ferrets].

The effects of magnesium (Mg) on afterdepolarisations and cesium-induced activity were studied in 15 preparations of ferret Purkinje fibres. When the perfusion medium was enriched with Mg to concentrations of 5 mM, the duration of the action potentials stopped increasing and the diastolic membrane potential was stabilised despite persistent exposure to cesium. A suppressor effect of Mg on the high and low voltage early afterdepolarisations was observed which was significant at 2.2 mM (p less than 0.03) and even more so at 5 mM (p = 3. 10-5) related to a lower probability of early afterdepolarisations. A suppressor effect of Mg on high and low voltage induced activities was also recorded, significant at 5 mM, due to a reduction in the probability of apparition of a first induced action potential (p = 2. 10-4) and a reduction in the number of induced action potentials (p = 8. 10-4). The rapid onset of action (a few minutes) of Mg suggests an extracellular mode of action. The suppressor effect of Mg is probably related to inhibition of an unmasked current by the cesium, a calcium antagonist effect and/or non-specific membrane stabilising effect. The suppressor effect of Mg on early afterdepolarisations and induced activity could, at least partially, explain its in vito antiarrhythmic action on torsades de pointe.

Action Potentials↗
PubMed1990

[Determination of cesium in human placenta 3 years after Chernobyl].

Three years after the nuclear reactor accident in Chernobyl, 80 human placentae were tested to determine concentrations of cesium 134 and cesium 137 radionuclides. The activities of radionuclides were measured using a low-back ground gamma-ray spectrometry system. Human placentae were obtained from normal and at term pregnancies in women who lived in rural areas of northern-Italy and north-west of Yugoslavia and who in particular used locally grown vegetables and meats. According to the data of other Authors, the low cesium isotopes 134 and 137 levels detected (inferior to 2 Bq/kg) in human placentae suggest that, in the observed geographic areas, the fetal risk following the reactor accident in Chernobyl was negligible.

Accidents↗
PubMed1990

[Cesium transfer in short food chains].

An investigation of 25,000 samples of foodstuffs and feedstuffs in Czechoslovakia, contaminated by fall-out cesium after the accident in the Chernobyl nuclear power plant, performed from May 5, 1986 to March 31, 1988, revealed that both the values of cesium transfer-factors in food--animal tissues--milk transitions and the values of biological half-life of cesium are functions of internal and external conditions of contamination. Organism individuality as the main internal condition causes the variance of about +/- 50% of the mean value of the respective transfer-factor. Through the external conditions, mainly the environmental contamination level, type of ingested food and time of ingestion, the mean values of transfer-factors are influenced up to 500%, e.g. to the value of 0.5. But this value converges with growing up contamination of food and environment to the limit of 0.3. The first two to three biological half-lives after the last ingestion of contaminated food are up to ten-times shorter than those at stabilized state.

Accidents↗