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[Increased levels of cesium-137 and cesium-134 in 34 mushroom species following the reactor accident at Chernobyl].

From September to December of 1986, 85 samples of 34 species of wild mushrooms were collected, mostly in northern Baden and occasionally in neighboring areas. Cs-137, Cs-134, and the natural nuclide K-40 were determined by gamma-spectrometry. Samples from the Rhine Valley and the Kraichgau were generally much less contaminated than those from the Black Forest. With one exception, their radiocesium levels were below the Common Market limit of 600 Bq/kg. The exception was a sample of Laccaria amethystina with 1710 Bq/kg Cs-137 and 766 Bq/kg Cs-134. Relatively high levels were also found in Xerocomus badius, X. chrysenteron and Cantharellus tubaeformis. The hymenophore contained higher concentrations of radiocesium than the other parts of the body of the fruit. No correlation between the concentration of K-40 and that of the Cs nuclides was found. The ratio of Cs-137:Cs-134 was usually below 3 but reached the value of 11.8 in Piptoporus betulinus growing on birch wood. In this case, the substrate must have contained more radiocesium from the time before the Chernobyl reactor accident than from the time thereafter.

Accidents↗

[Radioactive cesium 137 and cesium 134 in follicle and seminal fluid].

Radioactive caesium nuclids were measured in follicular fluid and seminal plasma after the nuclear power station accident of Chernobyl. Immediately after the event (June - Aug. 86) both Cs 137 and Cs 134 were negative, with the exception of one sample. Increased levels of Cs 137 were found in the next three periods of measurement (Nov. 86 - Jan. 87), (June - Aug. 87), (March 88), with the highest results one year after the accident. Increased levels of Cs 134 were found only in the last two periods of measurement. In seminal plasma, both Cs 137 and Cs 134, were elevated in some samples. An influence on the results of IVF was not registered.

Accidents↗

[Mobility of cesium-137, sodium and potassium in different types of soil and prediction of cesium-137 accumulation in agricultural plants].

Mobility of caesium-137, sodium and potassium in the natural environment in podzolic gray and chernozem medium-loamy, sward podzolic sandy soils and chernozem has been studied. Durability of fixation of caesium-137 increases in a number of soils: sward-podzolic sandy, podzolic loamy soils, chernozem. Caesium-137 concentration in agricultural plants is reduced along with the increase of caesium-137 fixation in soils and increase of the level of metabolic potassium. Coefficients of transition of metabolic caesium-137 by potassium and sodium, and of sodium by potassium. The mentioned above coefficients can be used for the prediction of caesium-137 cumulation in plants.

Agriculture↗

[Content of radioactive cesium in selected food products. Radioactive cesium in daily food rations of selected population groups].

The content of radioactive caesium isotopes emitting beta radiation was studied in daily food rations analysed in diets of working-class and non-working-class families from food products from the regions of Olsztyn, Poznań, Lublin, Warsaw and Wrocław in 1987 and 1988. In 1987 the highest level of radioactive caesium was found in the food rations in Olsztyn, and the lowest in the rations in Poznań (3.32 and 0.65 Bq/kg respectively). In 1988 higher radio-caesium content was found in rations composed according to the data on the diet consumed daily in non-working-class families. In that case the highest content was in the daily food ration composed in Warsaw--2.35 Bq/kg, and lowest in Poznań--1.19 Bq/kg. In the daily food rations of working-class families about one half of that value was found. The calculated mean values of both analysed rations were: 1.35 for Olsztyn, 0.89 for Poznań, and 1.86 Bq/kg for Warsaw. The calculated mean value of the contamination with radioactive caesium was in 1988 0.93 Bq/kg for the rations in working-class families (in 1987 it was 1.80 Bq/kg).

Cesium Radioisotopes↗

Principles determining the structure of high-pressure forms of metals: The structures of cesium(IV) and cesium(V).

Consideration of the relation between bond length and bond number and the average atomic volume for different ways of packing atoms leads to the conclusion that the average ligancy of atoms in a metal should increase when a phase change occurs on increasing the pressure. Minimum volume for each value of the ligancy results from triangular coordination polyhedra (with triangular faces), such as the icosahedron and the Friauf polyhedron. Electron transfer may permit atoms of an element to assume different ligancies. Application of these principles to Cs(IV) and Cs(V), which were previously assigned structures with ligancy 8 and 6, respectively, has led to the assignment to Cs(IV) of a primitive cubic unit cell with a = 16.11 A and with about 122 atoms in the cube and to Cs(V) of a primitive cubic unit cell resembling that of Mg(32)(Al,Zn)(49), with a = 16.97 A and with 162 atoms in the cube.

Journal Article↗

Cesium induces spontaneous epileptiform activity without changing extracellular potassium regulation in rat hippocampus.

Cesium has been widely used to study the roles of the hyperpolarization-activated (I(h)) and inwardly rectifying potassium (K(IR)) channels in many neuronal and nonneuronal cell types. Recently, extracellular application of cesium has been shown to produce epileptiform activity in brain slices, but the mechanisms for this are not known. It has been proposed that cesium blocks the K(IR) in glia, resulting in an abnormal accumulation of potassium in the extracellular space and inducing epileptiform activity. This hypothesis has been tested in hippocampal slices and cultured hippocampal neurons using potassium-sensitive microelectrodes. In the present study, application of cesium produced spontaneous epileptiform discharges at physiological extracellular potassium concentration ([K(+)](o)) in the CA1 and CA3 regions of hippocampal slices. This epileptiform activity was not mimicked by increasing the [K(+)](o). The epileptiform discharges induced by cesium were not blocked by the N-methyl-D- aspartate (NMDA) receptor antagonist AP-5, but were blocked by the non-NMDA receptor antagonist CNQX. In the dentate gyrus, cesium induced the appearance of spontaneous nonsynaptic field bursts in 0 added calcium and 3 mM potassium. Moreover, cesium increased the frequency of field bursts already present. In contrast, ZD-7288, a specific I(h) blocker, did not cause spontaneous epileptiform activity in CA1 and CA3, nor did it affect the field bursts in the dentate gyrus, suggesting that cesium induced epileptiform activity is not directly related to blockade of the I(h). When potassium-sensitive microelectrodes were used to measure [K(+)](o), there was no significant increase in [K(+)](o) in CA1 and CA3 after cesium application. In the dentate gyrus, cesium did not change the baseline level of [K(+)](o) or the rate of [K(+)](o) clearance after the field bursts. In cultured hippocampal neurons, which have a large and relatively unrestricted extracellular space, cesium also produced cellular burst activity without significantly changing the resting membrane potential, which might indicate an increase in [K(+)](o). Our results suggest that cesium causes epileptiform activity by a mechanism unrelated to an alteration in [K(+)](o) regulation.

2-Amino-5-phosphonovalerate↗

Central action of cesium chloride in streptozotocin-diabetic mice.

The changes in the pharmacological responses to cesium were examined in streptozotocin(STZ)-induced diabetic mice. An acute administration of cesium chloride (10 mEqCs+/kg IP) to non-diabetic control mice elicited increased salivation and inhibition of respiration followed by death in about half of the animals examined. These effects of cesium were diminished in STZ-diabetic mice. LD50 for acute cesium was higher in STZ-diabetic mice (14.3 mEq/kg) than non-diabetic buffer controls (11.7 mEq/kg): however, subchronic administration of cesium did not decrease the LD50 in STZ-diabetic mice. The sleeping time induced by pentobarbital was reduced in STZ-diabetic mice and the reduction of the pentobarbital-induced hypnosis was reversed by subchronic cesium pretreatment but not by acute cesium administration. Methamphetamine-induced mortality was increased in STZ-diabetic mice and acute administration of cesium decreased the toxicity in both control and diabetic mice. Inhibition of locomotor activity elicited by acute single injection of cesium chloride was observed in both STZ-diabetic and non-diabetic mice. These results indicate that responses to cesium as well as centrally-acting drugs are affected differentially in STZ-diabetic mice.

Animals↗

Pharmacologic response of cesium-induced ventricular tachyarrhythmias in anesthetized dogs.

Cesium chloride administration causes ventricular tachyarrhythmias in dogs, with many of the features of the clinical long QT syndrome. We developed a model of cesium-induced arrhythmias, using loading and maintenance doses of cesium to produce continuous cesium effects. The purpose of the present experiments was to study the response of arrhythmias in this model to a variety of pharmacologic interventions. Cesium chloride caused ventricular tachyarrhythmias that either degenerated to ventricular fibrillation (VF) or remained stable for greater than 30 min. Cesium-induced arrhythmias were suppressed by the calcium antagonist diltiazem, magnesium chloride, beta blockade (with atenolol), or vagal nerve stimulation--all interventions that can suppress calcium entry. beta-Adrenergic stimulation with isoproterenol initiated ventricular arrhythmias in the presence of subarrhythmic doses of cesium. Sodium channel blockers (lidocaine and high concentrations of quinidine) also suppressed cesium-induced arrhythmias. Intravenous (i.v.) bolus doses of isotonic saline solution at times corresponding to the other interventions studied did not alter the severity of cesium-induced arrhythmia. We conclude that cesium-induced ventricular arrhythmias in this model are suppressed by agents that reduce transmembrane calcium currents as well as by high doses of sodium channel blockers. These findings may have relevance to the mechanisms of, and the therapeutic approach to, the clinical long QT syndrome.

Animals↗