On the rubidium and lithium content and availability in the sub-arid south-eastern Mediterranean: potential health implications.

Rubidium and lithium are rather rare elements in environmental research, despite their affiliation with a group of chemically active metals and the abundance of Rb in the environment. A growing body of evidence, although controversial, has indicated that both elements possess unique essential and neurophysiological characteristics in biota and humans. Both elements may concentrate in soil and vegetation of sub-arid environments. We investigated the content and (potential) availability of Rb and Li in the soils and natural waters of Galilee, the Coastal Plain, and the northern Negev of Israel. A newly developed chromatographic technique for the separation of truly dissolved Rb and Li compounds has been applied. High concentrations of Rb, together with high values of the potentially vital Rb-to-K ratio, were found in the soils, the soil solutions, rainwater, throughfall water, and the plant litter leachates, but not in the surface and spring waters. This may indicate a sequestration of Rb in the local soils and a semi-closed Rb turnover in the soil-plant system with a major input from sea aerosols. Low Li bulk and available concentrations were determined in all the natural compartments. Possible implications of such specific environmental features on the local population health were discussed.

Risk assessment visualization of rubidium compounds: comparison of renal and hepatic toxicities, in vivo.

Rubidium has been considered to be nontoxic. Its use includes thin film on glass deposition and as medical contrast medium. Recent technology innovations also involve the use of rubidium, but there is limited information about the biological effects of its various compounds. In the present risk assessment study, a series of rubidium compounds with different counter anions-acetate, bromide, carbonate, chloride, and fluoride-were orally administrated in a single dose to several groups of rats. Cumulative 24-h urine samples were obtained, and the levels of rubidium, fluoride, N-acetyl-ß-D-glucosaminidase and creatinine were measured to evaluate possible acute renal effects. Daily samples of serum were also obtained to determine the levels of aspartate and alanine aminotransferases to assess possible acute hepatic effects. Urinary rubidium excretion recovery of 8.0-10.5% shows that urine can be a useful diagnostic tool for rubidium exposure. The present results reveal that rubidium shows different biological effects depending on the counter anion. A pattern of large significant NAG leakage and elevation of ALT observed in rats treated with anhydrous rubidium fluoride indicates renal and hepatic toxicities that can be attributed to fluoride. The techniques reported in this study will be of help to assess the potential risks of toxicity of rubidium compounds with a variety of anions.

[Migration and transformation of anthropogenic platinum group elements in environment: a review].

Anthropogenic platinum group elements (PGEs) are widely applied in vehicle exhaust catalytic converters (VECs), industrial catalysts, and pharmaceutics, making the PGEs, especially Pt, Pd, and Rh, become the newly environmental pollutants in some fields. Given the positive correlations between the Pt/Pd and Pt/Rh ratios in various environmental samples and the active components of VECs, the VECs containing PGEs as catalysts are regarded as the primary source of PGEs pollution. Sufficient reports indicated that in the past three decades, there was a significant increase of PGEs concentrations in diverse environmental matrices like airborne particulate matters, aquatic ecosystem components (e.g., river water, rain water, groundwater, seawater, and sediments), soils, road dusts, and organisms. It was generally assumed that anthropogenic PGEs behave in inert manner, and the health risks associated with the environmental exposures to PGEs are minimal. However, the recent studies on PGEs toxicity and environmental bioavailability indicated that once entering environment, anthropogenic PGEs might easily be mobilized and transformed into more toxic forms under the actions of various biogeochemical processes, and thereby, enhanced their bioavailability and posed potential health risks to human beings through food chain. This paper summarized the research results about the sources, distribution, and biogeochemical behaviors of PGEs in various environmental media, and it was considered that to establish the standards of PGEs for human health risks, to develop standard substances of PGEs for environmental measurements, to study the PGEs in the sediments of marginal seas, and to assess the toxicity of PGEs to marine mollusks, the present contamination status of PGEs in foods, and the risks of PGEs to human health would be the hot research topics in the future.

Rubidium marking of Anopheles mosquitoes detectable by field-capable X-ray spectrometry.

We present a mosquito marking technique suitable for mark-release-recapture that can be used with a hand-held, portable X-ray fluorescence (XRF) spectrometer, which is practical for field measurements. Third instar Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) and Anopheles stephensi Liston larvae were cultured to pupation in water containing rubidium (Rb) Cl at concentrations up to 1000 p.p.m. Rb. Anopheles gambiae larvae survived to adulthood at concentrations as high as 1000 p.p.m. Rb but suffered pupal mortality and reduced adult longevity at high concentrations. We were able to culture An. stephensi at Rb concentrations as high as 300 p.p.m. The presence of Rb in adults was evaluated using a portable XRF analyser, and we were able to reliably detect Rb above background levels in 10-day-old females and 4-day-old males at concentrations causing minimal pupal or adult mortality. We observed that Rb marking was not permanent, and the concentration declined significantly as adults aged. The low cost of labelling with RbCl and the field portability of the spectrometer provide a useful means for labelling mosquitoes via breeding sites or in the laboratory for mark-release-recapture experiments.

Rubidium is a possible supporting element for bone marrow leukocyte differentiation.

In the present paper the possible role of rubidium (Rb) on leukocyte differentiation is evaluated. When the metal was added to human mononuclear bone marrow cells cultured for 14 days in soft agar, it was able to increase the number of clusters and to reduce the number of colonies. This activity depended upon the presence of conditioned medium. Rb induced a faster differentiation of HL 60 cells cultured in a medium able to promote granulocyte differentiation. The metal did not show any activity on continuously cultured HL 60. These data suggest that Rb is a supporting element for cell differentiation. Toxicity tests on rats are also reported.

Studies on the mechanism of rubidium-induced kaliuresis.

Renal clearance and electron microprobe methods were used 1) to elucidate the effects of chronic rubidium administration on potassium transport and 2) to localize, by the use of amiloride in acute experiments, the tubule site of interaction between rubidium and potassium. Substitution of drinking water by a 50 mM rubidium chloride solution for 9 to 11 days led to significant hypokalemia (plasma potassium 2.5 +/- 0.1 mM; plasma potassium plus rubidium 3.3 +/- 0.1 mM). Compared to a control group (reduction of plasma potassium to 3.4 +/- 0.1 mM by short-term potassium depletion) with a fractional potassium excretion of 2.1 +/- 0.3%, rubidium-treated rats excreted potassium at a much higher rate of 14.6 +/- 3.0%. The potassium content of principal cells was, however, significantly lower in rubidium-treated than in potassium-deprived animals. Similar to experiments in which rubidium was given acutely (3 hours), chronic rubidium administration was associated with preferential accumulation of rubidium in all tubule cells relative to potassium. Rubidium clearances were uniformly below those of potassium. Amiloride abolished the difference between rubidium and potassium clearances and sharply reduced the excretion of both cations. In view of the known site of action of amiloride, this suggests a distal tubule site of rubidium action on potassium transport. Amiloride also reduced or abolished the preferential uptake of rubidium into all but intercalated tubule cells. Marked cell heterogeneity of rubidium accumulation into intercalated cells was observed: One subpopulation, with low cell chloride, retained rubidium more effectively than another subpopulation with high cell chloride.

Inhibitory effects of some organometallic complexes of rhodium(I) and iridium(I) on carrageenin paw edema in rats.

A group of 4 organometallic complexes of Rhodium (I) and 1 Iridium(I) was tested for the evaluation of their anti-inflammatory activity on carrageenin paw edema in rats. All the compounds used inhibited the development of paw edema by more than 50% at different dose-levels. The activity of the pyridinalmethylimine derivative [Rh(COD)PMI]+ Cl- had better results than that of [Rh(NBD)PMI]+ Cl- and even more than the dimeric complexes tested. The higher activity of [Ir(COD)Cl]2 as compared with [Rh(COD)Cl]2 suggests that it would be of interest to examine further Iridium(I) complexes, among which [Ir(COD)PMI]+ Cl- could be a good candidate.

Experimental comparative renal toxicity of lithium and rubidium.

Rat kidney was perfused using Krebs solution containing 3 or 6 mEq/l lithium or 3 or 6 mEq/l rubidium; the histological lesions thus induced were compared. Rubidium-induced lesions, irrespective of concentrations, consisted of tubular dilations, degeneration and necrosis very similar to those induced by lower concentrations of lithium; moreover, Bowman space alterations were observed. In contrast, lithium-induced damage was dose-dependent: 6 mEq/l solution induced severe tubular damage with necrosis, endoluminal cellular debris and hyaline substance.

[New vistas on rubidium]. / Point actuel sur le rubidium.

Rubidium salts have been used in human therapy since the end of the last century. The fact that an actual use in psychiatry has been considered is mainly due to Meltzer and al's works in 1969. The pharmacological studies do not reveal any psychopharmacological "provile" presently known; they point out that Rubidium has stimulant properties, whick, in certain conditions, can increase activity, central excitability and sometimes aggressiveness, among the animals used for the experiments. The hypothesis of a contingent antidepressant action of Rubidium is essentially based on the existence of properties opposite to those of Lithium. This is especially true in the biochemical field: Rubidium may enhance the release of Norepinephrine whereas Lithium has an opposite effect. The toxicological studies show that, because of some properties common to Rubidium and Potassium, it is necessary to control Potassium intake and to avoid that Rubidium replace too high a percentage of this ion: the extended half-life (about forty days in man) makes necessary the working up of chronical studies to evaluate the toxicity which is linked to its long-term accumulation. For Rubidium blood concentrations superior to 1 mEq/1., the first clinical studies seem to point out that an antidepressant action would exist. Nevertheless a certain delay of action is necessary to the onset of a therapeutic effect; no noticeable adverse effect has been detected.