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Frontiers in Endocrinology 2022While participating in an intensive training process, the athlete's body requires not only energy, but also specific macro- and microelements. The purpose of this study...
While participating in an intensive training process, the athlete's body requires not only energy, but also specific macro- and microelements. The purpose of this study was to show the meaning of monitoring the level of mineral trace elements in athletes-wrestlers during physical activity. As an experimental group, 66 male wrestlers aged 18-20 years with at least 3 years of intensive wrestling experience were examined. The control group consisted of 92 young cadets of military school aged 18-20 years, who had previous sports training, but were not engaged in wrestling. To determine the quantitative content of trace elements, the hair was cut from the back of the head for the entire length in an amount of at least 0.1 g. an examined using the mass spectrometer ICP-MS Agilent 7900. Strong positive correlations were found for sodium with potassium and rubidium, magnesium with calcium, potassium with rubidium, and rubidium with caesium among wrestlers. Wrestlers were found to have higher levels of a number of macro- and microelements, including toxic ones.
Topics: Child; Hair; Humans; Male; Potassium; Rubidium; Trace Elements; Wrestling
PubMed: 36034451
DOI: 10.3389/fendo.2022.985297 -
Angewandte Chemie (International Ed. in... Sep 2021Azadithiolate, a cofactor found in all [FeFe]-hydrogenases, is shown to undergo acid-catalyzed rearrangement. Fe [(SCH ) NH](CO) self-condenses to give Fe [(SCH ) N]...
Azadithiolate, a cofactor found in all [FeFe]-hydrogenases, is shown to undergo acid-catalyzed rearrangement. Fe [(SCH ) NH](CO) self-condenses to give Fe [(SCH ) N] (CO) . The reaction, which is driven by loss of NH , illustrates the exchange of the amine group. X-ray crystallography reveals that three Fe (SR) (CO) butterfly subunits interconnected by the aminotrithiolate [N(CH S) ] . Mechanistic studies reveal that Fe [(SCH ) NR](CO) participate in a range of amine exchange reactions, enabling new methodologies for modifying the adt cofactor. Ru [(SCH ) NH](CO) also rearranges, but proceeds further to give derivatives with Ru-alkyl bonds Ru [(SCH ) N][(SCH ) NCH ]S(CO) and [Ru [(SCH ) NCH ](CO) ] S.
Topics: Aza Compounds; Coordination Complexes; Hydrogenase; Models, Molecular; Molecular Structure; Rubidium; Toluene
PubMed: 34324230
DOI: 10.1002/anie.202108135 -
Journal of Neurochemistry Feb 1986Free 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...
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.
Topics: 3-O-Methylglucose; Acetaldehyde; Allopurinol; Aminoisobutyric Acids; Animals; Capillaries; Cerebrovascular Circulation; Dose-Response Relationship, Drug; Free Radicals; Hydrogen Peroxide; Hypoxanthine; Hypoxanthines; Male; Methylglucosides; Oxygen; Rats; Rats, Inbred Strains; Rubidium; Sodium-Potassium-Exchanging ATPase; Time Factors; Xanthine Oxidase
PubMed: 3001225
DOI: 10.1111/j.1471-4159.1986.tb12981.x -
Kidney International Aug 1989Renal clearance and electron microprobe methods were used 1) to elucidate the effects of chronic rubidium administration on potassium transport and 2) to localize, by...
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.
Topics: Amiloride; Animals; Electrolytes; Glomerular Filtration Rate; Kidney; Male; Potassium; Potassium Deficiency; Rats; Rats, Inbred Strains; Reference Values; Rubidium
PubMed: 2779091
DOI: 10.1038/ki.1989.177 -
Metal Ions in Life Sciences 2016Metal ions are essential cofactors for the structure and functions of nucleic acids. Yet, the early discovery in the 70s of the crucial role of Mg(2+) in stabilizing...
Metal ions are essential cofactors for the structure and functions of nucleic acids. Yet, the early discovery in the 70s of the crucial role of Mg(2+) in stabilizing tRNA structures has occulted for a long time the importance of monovalent cations. Renewed interest in these ions was brought in the late 90s by the discovery of specific potassium metal ions in the core of a group I intron. Their importance in nucleic acid folding and catalytic activity is now well established. However, detection of K(+) and Na(+) ions is notoriously problematic and the question about their specificity is recurrent. Here we review the different methods that can be used to detect K(+) and Na(+) ions in nucleic acid structures such as X-ray crystallography, nuclear magnetic resonance or molecular dynamics simulations. We also discuss specific versus non-specific binding to different structures through various examples.
Topics: Cesium; Crystallography, X-Ray; DNA; Hydrogen Bonding; Magnetic Resonance Spectroscopy; Models, Molecular; Nucleic Acid Conformation; Potassium; RNA; Rubidium; Sodium
PubMed: 26860302
DOI: 10.1007/978-3-319-21756-7_6 -
The Journal of Physiology Nov 19711. The Na content of rat red cells was found to be 4.40 m-mole/l. cells. When incubated in K(Rb)-free Na this value was doubled in 1 hr, whereas in K(Rb)-free choline it...
1. The Na content of rat red cells was found to be 4.40 m-mole/l. cells. When incubated in K(Rb)-free Na this value was doubled in 1 hr, whereas in K(Rb)-free choline it was reduced to about 35% in the same period of time.2. In cells with elevated Na (13.70 m-mole/l.) the activation curve of Rb influx by external Rb reached the same V(max) in sodium as in choline. The shape of the curve was sigmoid in the first case (K(m) about 1.05 mM) and hyperbolic in the second (K(m) about 0.20 mM).3. The activation curve of rubidium influx by internal sodium was linear at least up to 12 m-mole/l. cells with a slope of 0.84. From this concentration it could increase more steeply, though the data is insufficient to assure it.4. In normal cells the efflux of Na in K(Rb)-free Na Ringer was 5.64 m-mole/l. cells. hr, and it was reduced to 4.32 m-mole by 10(-4)M ouabain. This was accompanied by a reduction of Na influx by 4.14 m-mole, representing then a Na-Na ouabain-sensitive exchange mechanism.5. At a concentration of 5 mM, external Rb increased Na efflux in 2.32 m-mole/l. cells. hr above the K(Rb)-free levels, and reduced Na influx by 2.13 m-mole.6. It is proposed that the Na pump is able to operate even in the absence of external K(Rb), though at reduced rate and on a Na-Na exchange basis (Na is the only monovalent cation in the bathing solution). External K(Rb) would have two actions: to increase the rate of shuttling of the carrier (catalytic effect) and to switch the Na-Na to a Na-K(Rb) exchange.7. These results raise a question of the real significance of the Na/K(Rb) ;coupling' ratio and the K-free effect on the Na pump mechanism.
Topics: Animals; Biological Transport, Active; Choline; Erythrocytes; In Vitro Techniques; Ouabain; Potassium; Rats; Rubidium; Sodium; Water
PubMed: 5133948
DOI: 10.1113/jphysiol.1971.sp009632 -
Biophysical Journal Jan 2016The ionic atmospheres around nucleic acids play important roles in biological function. Large-scale explicit solvent simulations coupled to experimental assays such as...
The ionic atmospheres around nucleic acids play important roles in biological function. Large-scale explicit solvent simulations coupled to experimental assays such as anomalous small-angle x-ray scattering can provide important insights into the structure and energetics of such atmospheres but are time- and resource intensive. In this article, we use classical density functional theory to explore the balance among ion-DNA, ion-water, and ion-ion interactions in ionic atmospheres of RbCl, SrCl2, and CoHexCl3 (cobalt hexamine chloride) around a B-form DNA molecule. The accuracy of the classical density functional theory calculations was assessed by comparison between simulated and experimental anomalous small-angle x-ray scattering curves, demonstrating that an accurate model should take into account ion-ion correlation and ion hydration forces, DNA topology, and the discrete distribution of charges on the DNA backbone. As expected, these calculations revealed significant differences among monovalent, divalent, and trivalent cation distributions around DNA. Approximately half of the DNA-bound Rb(+) ions penetrate into the minor groove of the DNA and half adsorb on the DNA backbone. The fraction of cations in the minor groove decreases for the larger Sr(2+) ions and becomes zero for CoHex(3+) ions, which all adsorb on the DNA backbone. The distribution of CoHex(3+) ions is mainly determined by Coulomb and steric interactions, while ion-correlation forces play a central role in the monovalent Rb(+) distribution and a combination of ion-correlation and hydration forces affect the Sr(2+) distribution around DNA. This does not imply that correlations in CoHex solutions are weaker or stronger than for other ions. Steric inaccessibility of the grooves to large CoHex ions leads to their binding at the DNA surface. In this binding mode, first-order electrostatic interactions (Coulomb) dominate the overall binding energy as evidenced by low sensitivity of ionic distribution to the presence or absence of second-order electrostatic correlation interactions.
Topics: Cobalt; DNA, B-Form; Rubidium; Static Electricity; Strontium
PubMed: 26789755
DOI: 10.1016/j.bpj.2015.12.011 -
Brain and Behavior Mar 2019The applicability of "Rubidium Chloride, Rb from Generator" radiopharmaceutical for brain tumors (BT) diagnostics is demonstrated on the basis of the application...
INTRODUCTION
The applicability of "Rubidium Chloride, Rb from Generator" radiopharmaceutical for brain tumors (BT) diagnostics is demonstrated on the basis of the application experience of the radiopharmaceutical in neurooncology.
EXPERIMENTAL
A total of 21 patients with various brain tumors and nonneoplastic abnormal brain masses were investigated.
RESULTS AND DISCUSSIONS
The results of the imaging and differential diagnostics of malignant and benign tumors, nonneoplastic abnormal brain masses and lesions revealed the prevalence of high uptake of the radiopharmaceutical in the malignant tumors in comparison with benign glioma and arteriovenous malformations in which Rb-chloride accumulates in the vascular phase but does not linger further. The ultra-short half-life of radionuclide Rb (76 s) along with a low absorbed radiation dose with Rb-chloride by intravenous administration create a new possibility of successive use of two or more radiopharmaceuticals for the examination of the same patient. For instance, PET examination with F-FDG, C-methionine, C-choline, or any other radiopharmaceutical can be carried out in just 7-15 min. after Rb-chloride injection.
CONCLUSION
Research demonstrated an effectiveness of Rb-chloride application as a diagnostic agent in neurooncology. A method of dosing and administration of the generator-produced radiopharmaceutical has been worked out. It is possible to do up to 600 PET sessions using one Russian Rb generator GR-01. The generator is proved to be reliable and easy to use. The interest in Rb-chloride as a tumor-seeking radiopharmaceutical rose due to the active application of the modern devices PET/CT in the routine clinical practice.
Topics: Brain; Brain Neoplasms; Chlorides; Diagnosis, Differential; Humans; Medical Oncology; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals; Rubidium; Strontium Radioisotopes
PubMed: 30729720
DOI: 10.1002/brb3.1212 -
Quarterly Journal of Experimental... Apr 1986The efflux of 42K+ and 86Rb+ has been studied in collagenase-isolated normal mouse islets of Langerhans. In double-labelled experiments, the ratio of efflux rate...
The efflux of 42K+ and 86Rb+ has been studied in collagenase-isolated normal mouse islets of Langerhans. In double-labelled experiments, the ratio of efflux rate constants of Rb+ and K+ (kRb/kK) was 0.80 in 5 mM-K+ and 0 glucose. The ratio was unaffected by glucose concentrations up to 22.2 mM. In the presence of 50 mM-K+, 0 glucose, the ratio increased to 0.91 and in 50 mM-Rb+, 0 glucose and 0 K+, the ratio was 1.06. With these limitations, the results indicate that 86Rb+ is an acceptable isotope for K+. Using the Goldman model, K+ and Rb+ permeability coefficients and K+ slope and chord conductances were computed. The permeabilities decreased in glucose and in high K+ or high Rb+. In the case of high external K+, the K+ conductances increased. Also there may be more than one type of K+ channel with differing selectivities to K+ and Rb+. The addition of glucose in the presence of 50 mM-K+ had no further effect on Rb+ permeability. It is suggested that there are about ten small K+ channels open in the resting beta-cell and that progressive closure of these channels is involved in the depolarization of the cell membrane that initiates spike activity.
Topics: Animals; Cell Membrane Permeability; Electric Conductivity; Glucose; Islets of Langerhans; Mice; Osmolar Concentration; Potassium; Potassium Radioisotopes; Radioisotopes; Rubidium
PubMed: 3520625
DOI: 10.1113/expphysiol.1986.sp002979 -
The Journal of Physiology Jul 19801. A three-electrode voltage clamp method was used to investigate the Rb block of inward rectification in frog sartorius muscle fibres. 2. In a solution containing 80...
1. A three-electrode voltage clamp method was used to investigate the Rb block of inward rectification in frog sartorius muscle fibres. 2. In a solution containing 80 mM-K+, the potassium conductance increased with increasing hyperpolarization to 3.18 +/- 0.11 mS. cm-2 (n = 17) when (V - VK) was -150 mV. In the presence of Rb+, the conductance increased, fell and increased again with increasing hyperpolarization, i.e. the Rb block was first increased and then reduced by increasing hyperpolarization. Increasing [Rb]o increased the block at all voltages. 3. In a solution containing 80 mM-Rb+ (zero K+) inward currents were recorded when the membrane was hyperpolarized beyond about -60 mV. These currents, which were < 10% the amplitude of those in 80 mM-K solution, were blocked by tetraethylammonium ions. 4. Experiments were carried out in solutions either where both [K]o and [K]i were increased, or where [K]o only was increased. The form of the relation between K conductance and membrane potential appeared to depend on [K]o. The magnitude of the conductance appeared to depend on [K]o and on [K]i. 5. So far as the block by Rb+ is concerned, increasing [K]o appeared to enhance the release of Rb block under large hyperpolarizations. Increasing [K]o and [K]i reduced the Rb block at all membrane potentials. 6. The results of experiments in the presence of Rb+ and Cs+ suggest that these two ions do not compete with each other for a site at which they block inward rectification. Rather, over a range of membrane potentials from -25 to -65 mV, the presence of Cs+ enhances the Rb block and vice versa. 7. Single dissected muscle fibres (from semitendinosus) were used to measure sarcoplasmic resistivity in 80 mM-K solution and 160 mM-K (hyperosmotic) solution. The measured values were 163.2 +/- 11.7 omega x cm and 136.1 +/- 16.0 omega x cm, respectively (n = 7). 8. A semi-empirical model is presented, supposing that Rb interacts with a site in the membrane to produce its blocking effect, but is able to move on through into the sarcoplasm. Internal K+ is supposed to reduce the affinity of the site for Rb+; external K+ is able to enhance the moving on of Rb+ into the sarcoplasm. 9. The implications of our experiments for the nature of the permeability mechanism inward rectification are discussed.
Topics: Animals; Cesium; Electric Conductivity; In Vitro Techniques; Membrane Potentials; Muscles; Potassium; Ranidae; Rubidium; Sarcoplasmic Reticulum; Tetraethylammonium Compounds
PubMed: 7441543
DOI: 10.1113/jphysiol.1980.sp013333