Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RUBIDIUM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1959

Rubidium and cesium fluxes in muscle as related to the membrane potential.

The reduction of membrane potential in frog sartorius muscle produced by rubidium and cesium ions has been studied over a wide concentration range and compared with depolarization occasioned by potassium ions. The constant field theory of passive flux has been used to predict the potential changes observed. The potential data suggest certain permeability coefficient ratios and these are compared with ratios obtained from flux data using radioactive tracers. The agreement of the flux with the potential data is good if account is taken of the inhibition of potassium flux which occurs in the presence of rubidium and cesium ions. A high temperature dependence has been observed for cesium influx (Q(10) = 2.5) which is correlated with the observation that cesium ions depolarize very little at low temperatures. The observations suggest that cesium ions behave more like sodium ions at low temperatures and more like potassium ions at room temperature with respect to their effect on the muscle cell resting potential. The constant field theory of passive ion flux appears to be in general agreement with the experimental results observed if account is taken of the dependence of permeability coefficients on the concentrations of ions used and of possible interactions between the permeabilities of ions.

Animals↗
PubMed1965

The suppression of the late after-potential in rubidium-containing frog muscle fibers.

The late after-potential that follows trains of impulses in frog muscle fibers is virtually absent when most of the intracellular potassium is replaced by rubidium and the muscle is immersed in rubidium-containing Ringer's fluid. Its amplitude is also reduced in freshly dissected, potassium-containing muscle fibers that are immersed directly in Rb-Ringer's fluid. These findings are discussed in terms of the model for muscle membrane of Adrian and Freygang (1962 a, b) and in relation to the report of Adrian (1964) that Rb-containing muscle fibers do not exhibit the variations in potassium permeability as a function of membrane potential that are found in fibers with normal intracellular potassium concentration immersed in Ringer's fluid.

Animals↗
PubMed2004

Development of an HTS assay for Na+, K+-ATPase using nonradioactive rubidium ion uptake.

A high-throughput screening (HTS) assay was developed for the Na(+),K(+)-ATPase channel in order to study rubidium uptake as a measure of the functional activity and modulation of this exchanger. The assay uses elemental rubidium as a tracer for K(+) ions. Three cell lines were used to study the exchanger, and the assay was performed in a 96-well microtiter plate format. Rb(+) uptake was carried by the CHO-K1 cells at 37 degrees C; the maximum ion influx was at 80 min of incubation of the cell line in the medium containing 5.4 mM RbCl. The cells were incubated in Rb(+) uptake buffer (5.4 mM) and with the pump blocker ouabain for 1, 2, and 3 h, respectively. A complete block of the Rb(+) uptake was observed with a 5 mM concentration of ouabain for all the three time intervals. The ouabain 50% inhibitory concentration (IC(50)) value for CHO-K1 cell line ATPase was observed to be 298 microM after 3 h of incubation. In addition, IC(50) values of 94 and 89 microM were observed at 30 min of incubation, indicating that the protocol shows reproducible results. A Z' factor higher than 0.7 was observed in the assays. These studies extend the profile of Na(+),K(+)-ATPases and demonstrate the feasibility of this HTS assay system to screen for compounds that pharmacologically modulate the function of Na(+),K(+)-ATPase.

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↗
PubMed1991

Rubidium for marking adults of Culicoides variipennis (Diptera: Ceratopogonidae).

Culicoides variipennis adults were reared from media with nine concentrations of rubidium (Rb) ranging from 0.0 to 1,000 ppm. Rubidium levels were measured using an atomic absorption spectrophotometer. Concentrations of 500 and 1,000 ppm of Rb reduced pupal production, adult emergence, and adult longevity; lower levels of Rb had no noticeable effects. Adult females reared from media containing 15.6 ppm Rb were marked for a period of at least 13 d, and Rb levels were unaffected by a blood meal on day 3. One marked fly was readily detected in a pool of five. This technique should be useful in studying the dispersal behavior of C. variipennis under field conditions.

Animals↗
PubMed1994

Marking Dermacentor variabilis (Acari: Ixodidae) with rubidium.

Studies were conducted to determine the feasibility of marking Dermacentor variabilis (Say) with the alkali metal rubidium (Rb) by feeding larvae on mice that were injected with rubidium chloride (RbCl). Newly molted nymphs that fed as larvae for 2 to 5 d on RbCl-injected mice contained approximately 660 parts per billion (ppb) of Rb, whereas nymphs that had fed for 6 to 10 d as larvae on RbCl-injected mice contained 419 ppb of Rb. Nymphs that fed as larvae on control mice contained approximately 9 ppb. There was no host-specific difference in Rb concentration among nymphs obtained from four RbCl-injected mice. Rb-marked nymphs did not show reduced survival as compared with unmarked nymphs when survival was monitored for 8 wk. Rb concentrations in unfed nymphs remained close to 600 ppb for 3 wk, then declined to approximately 380 ppb for 5 wk. Rb concentrations in experimental nymphs remained significantly higher than in control nymphs for 8 wk. Adults that molted from Rb-marked nymphs that had fed on control mice did not contain elevated levels of Rb. This marking method has considerable potential for aiding in population ecology studies of ticks under natural conditions because ticks can be marked via their hosts and the mark will be retained for the duration of the life stage without passing the mark to subsequent stages.

Animals↗
PubMed1997

Unsuccessful rubidium marking of American dog tick (Acari:Ixodidae) adults.

In an effort to determine if Dermacentor variabilis (Say) adults could be marked with rubidium (Rb), unfed nymphs were placed on laboratory mice and the mice subsequently injected with rubidium chloride (RbCl). Nymphal feeding duration was not affected by the presence of Rb in their hosts. D. variabilis adults (24-48 h old) that had fed as nymphs on RbCl-injected hosts contained approximately 13 parts per billion (ppb) of Rb, and adults that had fed as nymphs on control mice contained approximately 20 ppb of Rb. There was no difference in Rb concentration among D. variabilis adults obtained from different RbCl-injected mice. Although Rb has been shown to be a noninvasive marker for D. variabilis nymphs, D. variabilis adults were not successfully marked using the same technique.

Animals↗
PubMed2006

Reversible light-controlled formation and evaporation of rubidium clusters in nanoporous silica.

We observe reversible light assisted formation and evaporation of rubidium clusters embedded in nanoporous silica. Metallic nanoparticles are cyclically produced and evaporated by weak blue-green and near-infrared light, respectively. The atoms photodetached from the huge surface of the silica matrix build up clusters, whereas cluster evaporation is increased by induced surface plasmon excitation. Frequency tuning of light activates either one process or the other and the related changes of glass transparency become visible to the naked eye. We demonstrate that the porous silica, loaded with rubidium, shows memory of illumination sequences behaving as a rereadable and rewritable optical medium. These processes take place as a consequence of the strong confinement of atoms and particles at the nanoscale.

Metal Nanoparticles↗
PubMed1986

Oxygen free-radical reduction of brain capillary rubidium uptake.

Free radicals are proposed to play a role in the injury following cerebral ischemia in which cerebral edema is a prominent feature. To determine whether free radicals might alter the movement of ions and water across the blood-brain barrier, we examined their effect on brain capillary transport. Rat brain capillaries were isolated, incubated with a system that generates free radicals, and various capillary transport systems were studied. Rubidium uptake was reduced 74% whereas rubidium efflux, glucose transport, and capillary water space were unchanged. The results following the addition of radical scavengers indicated that hydrogen peroxide or a related free radical was the toxic species. These data suggest that free radicals can impair capillary endothelial cell mechanisms that help maintain homeostasis of electrolytes and water in brain.

3-O-Methylglucose↗
PubMed1977

Effects of replacing medium sodium by choline, caesium, or rubidium, on water and ion contents of renal cortical slices.

1. Renal cortical slices from rat, rabbit, and guinea-pig were incubated in media in which choline, caesium or rubidium replaced sodium.2. Slices of rabbit and guinea-pig renal cortex incubated in oxygenated choline Ringer decreased in volume initially and did not swell over 3 hr at 25 degrees C. There was a steady loss of potassium. Inhibition of metabolism (N(2) + 1 mM iodoacetamide) caused some swelling. Ouabain, 10 mM, in choline Ringer affected neither loss of potassium nor tissue water content.3. Slices of rat renal cortex similarly incubated in choline Ringer swelled over 3 hr at 25 degrees C whether or not metabolism was inhibited; ouabain (15 mM) affected neither tissue potassium loss nor tissue water content.4. Incubation in choline Ringer containing either 0.2 mMp-chloromercuribenzoic acid, or 1 mM ethacrynic acid increased the tissue water content of guinea-pig renal cortical slices.5. Depletion of cellular potassium (by preliminary incubation in oxygenated potassium-free sodium Ringer with 10 mM ouabain at 30 degrees C) resulted in increased tissue water content when rabbit renal cortical slices were subsequently incubated in oxygenated choline Ringer at 25 degrees C for 3 hr.6. There was no evidence of energy-dependent extrusion of water or ions from either equilibrated rat or rabbit renal cortical slices leached at 0.5 degrees C and then reincubated at 25 degrees C in choline Ringer.7. Rat and guinea-pig renal cortical slices leached at 0.5 degrees C and reincubated at 25 degrees C swelled in rubidium Ringer and in caesium Ringer. There was no evidence of energy-dependent water or ion extrusion when metabolism was restored after leaching in either of these media. Metabolizing rat slices but not guinea-pig slices swelled faster than slices whose metabolism was inhibited.8. These results lend no support to the mechano-chemical hypothesis which ascribes cellular volume regulation to a contractile mechanism squeezing isotonic extracellular fluid from the cells. Instead it is suggested that cellular water content in these experiments reflects the balance between the rate of loss of potassium (and chloride) from the cells and the rate of uptake of extracellular cation (and chloride) into the cells - these rates reflecting both the electrochemical potential gradients of the ions and membrane permeability to them. The implications in relation to the hypothesis of ouabain-insensitive cellular volume regulation are discussed.

Animals↗
PubMed1978

Nerve fibre refractory period in patients treated with rubidium and lithium.

Nerve fibre refractory period distributions have been measured on the median nerves of six manic-depressive patients controlled with lithium carbonate, three chronic patients (two manic-depressives and one catatonic schizophrenic) controlled with rubidium chloride, and eight normal volunteers. Rubidium prolonged the refractory periods of all nerve fibres while lithium increased only the longer refractory periods.

Adult↗
PubMed1985

Kinetics of rubidium-82 after coronary occlusion and reperfusion. Assessment of patency and viability in open-chested dogs.

Currently available noninvasive techniques are unable to rapidly assess artery patency and tissue viability during acute myocardial infarction. In prior studies, rubidium-82 (Rb-82), a short-lived positron emitter obtained from a generator, was validated as an indicator of flow with a model that included the rate constants for transfer into and out of the cell. Accordingly, in the current study, 20 open-chested dogs with experimental infarction were studied serially at base line, after coronary occlusion, and at reperfusion. Time-activity curves acquired with beta probes on the epicardial surface were used to measure flow and net transfer of rubidium. Flow decreased to 0.41 +/- 0.08 ml/min per gram during occlusion and increased to 2.73 +/- 0.56 ml/min per gram in potentially viable ischemic tissue, whereas flows were 0.32 +/- 0.08 during occlusion (P less than 0.05 vs. viable) and 1.58 ml/min per gram (P less than 0.002 vs. viable) in irreversibly injured tissue. The transfer rate constant for Rb-82, kT, at base line was +1.22 +/- 0.60 X 10(-3) s-1 and did not change significantly during occlusion in viable vs. nonviable samples (+1.41 +/- 1.27 vs. +0.93 +/- 1.51 X 10(-3) s-1, respectively), except that 4 out of 11 nonviable tissue samples had negative kTs. At reperfusion, viable myocardial samples were all positive (+1.26 +/- 1.58 X 10(-3) s-1), whereas all irreversibly injured tissues had a negative kT, indicating leakage of tracer (-1.50 +/- 1.10 X 10(-3) s-1, P less than 0.001). This study suggests that Rb-82 time-activity curves can be useful to determine patency of an infarct related artery and potential viability after reperfusion during myocardial infarction.

Animals↗
PubMedDate not supplied

Memory storage and effect of repeated treatment with a new antidepressant drug: rubidium chloride.

Following 15 days' treatment with saline, 48 mg/kg rubidium chloride, 5 mg/kg imipramine hydrochloride, 10 mg/kg sodium phenobarbitone, 1000 mg/kg piracetam, or 0.20 mg/kg strychnine nitrate all administered intraperitoneally, mice were evaluated by habituation of exploratory activity using an open-field apparatus. In control animals a significant (P less than 0.05) decrease in open-field responses (ambulation, rearing and defaecation) was seen following a 1-day intersession interval and there was no retention of exploratory activity after a 5-day intersession interval. Administration of imipramine or phenobarbitone for 15 days was found to impair retention of memory after 1 day, whereas treatment with rubidium chloride, piracetam, or strychnine for 15 days improve retention after a 5-day intersession interval.

Animals↗
PubMed1977

Trace elements (zinc, cobalt, selenium, rubidium, bromine, gold) in human placenta and newborn liver at birth.

Concentrations of zinc, cobalt, selenium, rubidium, bromium, and gold have been determined by neutron activation analysis in 18 placental and 6 liver tissue samples at birth. Their respective mean concentrations +/- standard deviations (parts per million) were 58 +/- 10, 0.060 +/- 0.036, 1.90 +/- 0.41, 14.0 +/- 3.5, 26.9 +/- 14.3, and 0.31 +/- 0.14 in placenta, and 651 +/- 257, 0.156 +/- 0.077, 4.52 +/- 1.96, 9.2 +/- 3.7,11.2 +/- 4.1, and 0.12 +/- 0.06 in liver tissue. Thus, we observed that the mean concentrations of essential trace elements (zinc, cobalt, and selenium) were significantly higher in liver than in placenta, whereas the nonessential trace elements (rubidium, bromium, and gold) were found in significantly higher concentrations in placenta than in liver tissue.

Bromine↗
PubMed2000

Concentrations of copper, zinc, manganese, rubidium, and magnesium in thoracic empyemata and corresponding sera.

In this study, a number of selected trace elements and clinically relevant parameters were compared between thoracic empyemata and the corresponding sera for a better understanding of the trace element distribution between these two compartments. Serumempyema pairs were obtained from 13 patients and quantified for selected and essential trace elements, namely copper (Cu), zinc (Zn), manganese (Mn), rubidium (Rb), and magnesium (Mg), by inductively coupled plasma-mass spectrometry (ICP-MS). In addition, the concentrations of the following clinical laboratory parameters were analyzed by standard methods: total protein, leukocyte count, lactate dehydrogenase, glucose, pH, and the C-reactive protein. Individual concentrations of the elements determined in the empyemata were frequently higher than in pleural effusions of any other benign or malignant condition except for Cu. Serum Cu exceeded the normal range (600-1400 microg/kg) in 6 out of 13 patients (median 1410 microg/kg). In the empyemata, Zn concentrations (median 2000 microg/kg) were characteristically higher than in the sera (median 450 microg/kg) and exceeded the upper limit for serum (1200 microg/kg) in 8 of the 13 patients. Manganese concentrations in the empyemata (median 2.7 microg/kg) were also higher compared to corresponding sera, although they stayed within the limits considered normal for serum of healthy adults (upper limit 2.9 microg/kg). Rubidium was also moderately higher in most empyemata (median 290 microg/kg) and exceeded the upper limit for serum (560 microg/kg) in two patients. The median concentration of the essential element magnesium was higher in the empyemata (23 mg/kg) than in the sera (21 mg/kg). However, all serum Mg concentrations except three remained within the normal range (17-22 mg/kg). Removal of large amounts of empyematous fluid may deprive the body of trace elements and can cause suboptimal or deficient trace element status and homeostasis. Recuperation will be accelerated by compensatory supplementation of trace elements. Therefore, selective medication with adequate trace element compounds in patients with thoracic empyema can be generally recommended for zinc. The other elements need not necessarily be monitored or substituted, because of their stable concentrations in the serum. Rb may have a biological impact, but deficiency symptoms in man are not clearly defined.

Aged↗
PubMed1975

[Atomic absorption spectrophotometry of rubidium levels in several biological media. Technical problems and preliminary results].

The mean of Rubidium rates in human plasma is found in the range of 0,1 mg/l with poor fluctuations; it is significantly less in woman than in man. There is a good linear correlation between rates in plasma and in red cell, rates which are in the same relation than potassium ones. Mean urinary clearance of rubidium is 16 ml/mm but there are large variations.

Blood Viscosity↗
PubMed1991

Myocardial metabolism of fluorodeoxyglucose compared to cell membrane integrity for the potassium analogue rubidium-82 for assessing infarct size in man by PET.

Potassium loss from damaged myocardial cells is linearly related to CPK enzyme loss reflecting extent of necrosis. The potassium analog, rubidium-82 (82Rb), is extracted after i.v. injection and retained in viable myocardium but is not trapped or washed out of necrotic regions. To compare myocardial cell metabolism with membrane dysfunction as indicators of necrosis/viability, 43 patients with evolving myocardial infarction and coronary arteriography had positron emission tomography using fluorodeoxyglucose (FDG) and the potassium analog 82Rb. Percent of heart showing FDG defects and 82Rb washout on sequential images indicating failure to retain the potassium analogue were visually assessed and quantified by automated software. Infarct size based on rubidium kinetics correlated closely with size and location on FDG images (visual r = 0.93, automated r = 0.82), suggesting that loss of cell membrane integrity for trapping the potassium analog 82Rb parallels loss of intracellular glucose metabolism, both comparable quantitative markers of myocardial necrosis/viability.

Carbohydrates↗
PubMed1990

Quantitative in vivo measurements of tumor perfusion using rubidium-81 and positron emission tomography.

Rubidium-81 (t1/2 = 4.58 hr) was investigated as a tumor perfusion tracer in the VX2 carcinoma implanted into rabbit thigh muscle using a large-area, multiwire proportional chamber positron emission tomography (PET) system. Perfusion was determined using the arterial reference sample method, and the results from PET imaging were compared with postmortem tissue sampling. Absolute quantitation of tumor perfusion was achieved using external probes to estimate local extraction fraction. Redistribution of rubidium-81 (81Rb) was investigated using a dual-tracer technique. Average perfusion was found to be 13.5 and 3.7 ml/min/100 g in tumor and normal muscle, respectively. The extraction fraction as estimated from a two-compartment model ranged from 0.94 to 1.00. No significant redistribution of 81Rb was observed in these tissues. Nine patients with malignancies were studied using 81Rb and PET. Tumor perfusion in four patients with carcinoma of the breast was elevated by a factor of 1.8 (range 1.2-2.3) compared to contralateral normal breast.

Animals↗