Effects of Rubidium Chloride on the Course of Manic-Depressive Illness

Associations Between Plasma Metals and Cognitive Function in People Aged 60 and Above

The objective of the study was to explore the relationship between the plasma levels of 22 metals and cognition status in older adults aged 60 years and above. A cross-sectional survey was conducted between 2018 and 2019. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the concentrations of metals, and a mini-mental state examination (MMSE) questionnaire was used to estimate the cognition status of the elderly. Based on the years of education and MMSE scores, the participants were separated into the normal and impaired cognition groups. Lasso regression, logistic regression, and restricted cubic spline models were used to explore the relationship between the metals and cognitive status. A total of 1667 subjects were included in the study, and 333 (19.97%) of the participants had impaired cognition. Then, 12 metals, including Al, Fe, Ni, Cu, As, Se, Rb, Sr, Mo, Cd, Sn, and Sb were selected by lasso regression. Before the multivariate adjustment, Al and Cu were associated with the risk of increasing cognitive impairment (OR = 1.756, 95% CI: 1.166-2.646, P = 0.007; OR = 1.519, 95% CI: 1.050-2.197, P = 0.026, respectively). By contrast, Rb was associated with a decrease in the risk of cognitive impairment (OR = 0.626, 95% CI: 0.427-0.918, P = 0.017), but Cd was significantly associated with an increase in this risk (OR = 1.456, 95% CI: 1.003-2.114, P = 0.048). After multivariate adjustment, only Al (OR = 1.533, 95% CI: 1.000-2.350, P = 0.050) maintained a borderline difference with the risk of cognitive impairment. A significant positive correlation was found between the risk of cognitive impairment and Al, Cu, and Cd, contrary to the negative correlation found with Rb.

Peperomia pellucida (L.) Kunth and eye diseases: A review on phytochemistry, pharmacology and toxicology

Peperomia pellucida (L.) Kunth is a medicinal plant used to manage inflammatory illnesses such as conjunctivitis, and gastrointestinal and respiratory tract disorders in tropical and subtropical regions. However, little is known about its pharmacological mechanism of action against eye diseases. This review aims to critically discuss the phytochemistry, pharmacology and toxicology of P. pellucida as well as its roles in the treatment of cataract, glaucoma and diabetic retinopathy. Recent developments in the uses of P. pellucida for healthcare and nutraceutical products by the pharmaceutical industry are also covered in this review. For this review, a literature search was performed with PubMed, ScienceDirect, SciFinder Scholar and Scopus databases, using relevant keywords. Among the various phytochemicals identified from P. pellucida, β-caryophyllene, carotol, dillapiole, ellagic acid, pellucidin A, phytol and vitexin exhibit strong pharmacological activities within the mitogen-activated protein kinase and nuclear factor-κB signalling pathways in inflammatory eye diseases. The antihypertensive, anti-inflammatory, antioxidant, antihyperglycemic and anti-angiogenic activities displayed by P. pellucida extracts in many in vitro, in vivo and clinical studies suggest its potential role in the management of inflammatory eye diseases. P. pellucida extract was non-toxic against normal cell lines but displayed mild toxicity in animal models. The growing public interest in P. pellucida has inspired the nutraceutical and pharmaceutical industries to process the plant into health products. Although the potential pharmacological mechanisms against eye diseases have been summarized, further studies of the interactions among constituent phytochemicals from P. pellucida within various signalling pathways shall support the use of the plant as an alternative therapeutic source.

Trace elements in drinking water and the incidence of attention-deficit hyperactivity disorder

BACKGROUND

Trace elements have been suggested to have neurotoxic effects and increase the risk of neurodevelopmental disorders, but studies of a potential role of trace elements in relation to Attention-Deficit/Hyperactivity Disorder (ADHD) are very limited. The objective of this study was to conduct an exploratory analysis investigating the associations between 17 geogenic trace elements (Ba, Co, Eu, I, Li, Mo, Rb, Re, Rh, Sb, Sc, Se, Si, Sr, Ti, U and Y) found in Danish drinking water and the risk of developing ADHD.

METHODS

In this cohort study, 284,309 individuals, born 1994-2007, were followed for incidence of ADHD from the age of five until the end of study, December 31, 2016. We conducted survival analyses, using Poisson regression to estimate incidence rate ratios (IRRs) with 95 % confidence intervals (CI) in three different confounder adjustment scenarios.

RESULTS

In a model including adjustments for age, sex, calendar year, parental socio-economic status, neighborhood level socio-economic status and parental psychiatric illness, we found that six of the 17 trace elements (Sr, Rb, Rh, Ti, Sb and Re) were associated with an increased risk of ADHD, whereas two (Ba and I) were inversely associated with ADHD. However, when including region as a covariate in the model, most trace elements were no longer associated with ADHD or the association changed direction. Four trace elements (I, Li, Rb, and Y) remained significantly associated with ADHD but in an inverse direction and for three of these (I, Li and Y), we found significant interactions with region in their association with ADHD.

CONCLUSION

The trace elements under investigation, at levels found in Danish drinking water, do not seem to contribute to the development of ADHD and our findings highlight the importance of examining consistency of associations across geographic areas.

Rubidium chloride increases lifespan through an AMPK/FOXO-dependent pathway in Caenorhabditis elegans

AMP-activated protein kinase (AMPK) is involved in life span maintenance, stress responses, and germ cell cycle arrest upon dauer entry. AMPK is currently considered a promising target for preventing age-related diseases. Rubidium is one of the trace elements in human body. As early as the 1970s, RbCl has been was reported to have neuroprotective effects. In this work, we report the anti-aging effect of RbCl in Caenorhabditis elegans. Specifically, we reveal that (1) RbCl does increase the lifespan and enhance stress resistance in C. elegans without disturbing their fecundity. (2) RbCl induces superoxide dismutase (SOD) expression, which is essential for its anti-aging and anti-stress effect. (3) AAK-2 and DAF-16 are essential to the anti-aging efficacy of RbCl, and RbCl can promote DAF-16 translocating into the nucleus, suggesting that RbCl delays aging through regulating AMPK/FOXO pathway. RbCl can be a promising agent against aging related diseases.

Rubidium chloride modulated the fecal microbiota community in mice

Background

The microbiota plays an important role in host health. Although rubidium (Rb) has been used to study its effects on depression and cancers, the interaction between microbial commensals and Rb is still unexplored. To gain the knowledge of the relationship between Rb and microbes, 51 mice receiving RbCl-based treatment and 13 untreated mice were evaluated for their characteristics and bacterial microbiome changes.

Results

The 16S ribosomal RNA gene sequencing of fecal microbiota showed that RbCl generally maintained fecal microbial community diversity, while the shifts in fecal microbial composition were apparent after RbCl exposure. RbCl significantly enhanced the abundances of Rikenellaceae, Alistipes, Clostridium XlVa and sulfate-reducing bacteria including Deltaproteobacteria, Desulfovibrionales, Desulfovibrionaceae and Desulfovibrio, but significantly inhibited the abundances of Tenericutes, Mollicutes, Anaeroplasmatales, Anaeroplasmataceae and Anaeroplasma lineages. With regarding to the archaea, we only observed two less richness archaea Sulfolobus and Acidiplasma at the genus level.

Conclusions

Changes of fecal microbes may in part contribute to the anticancer or anti-depressant effects of RbCl. These findings further validate that the microbiome could be a target for therapeutic intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02095-4.

Beyond the Mind-Serum Trace Element Levels in Schizophrenic Patients: A Systematic Review

The alterations in serum trace element levels are common phenomena observed in patients with different psychiatric conditions such as schizophrenia, autism spectrum disorder, or major depressive disorder. The fluctuations in the trace element concentrations might act as potential diagnostic and prognostic biomarkers of many psychiatric and neurological disorders. This paper aimed to assess the alterations in serum trace element concentrations in patients with a diagnosed schizophrenia. The authors made a systematic review, extracting papers from the PubMed, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Among 5009 articles identified through database searching, 59 of them were assessed for eligibility. Ultimately, 33 articles were included in the qualitative synthesis. This review includes the analysis of serum levels of the following trace elements: iron, nickel, molybdenum, phosphorus, lead, chromium, antimony, uranium, magnesium, aluminum, zinc, copper, selenium, calcium, and manganese. Currently, there is no consistency regarding serum trace element levels in schizophrenic patients. Thus, it cannot be considered as a reliable prognostic or diagnostic marker of schizophrenia. However, it can be assumed that altered concentrations of those elements are crucial regarding the onset and exaggeration of either psychotic or negative symptoms or cognitive dysfunctions.

Recovery of Rubidium and Cesium Resources from Brine of Desalination through t-BAMBP Extraction

50 billion cubic meters of brine every year creates ecological hazards to the environment. In order to reuse brine efficiently, rubidium and cesium were recovered in this experiment. On the other hand, the main impurities which were needed to be eliminated in brine were lithium, sodium, potassium, calcium, and magnesium. In the procedure, seawater was distilled and evaporated first to turn into simulated brine. Perchloric acid was then added into simulated brine to precipitate potassium perchlorate which could reduce the influence of potassium in the extraction procedure. After that, t-BAMBP and ammonia were separately used as extractant and stripping agent in the extraction and stripping procedures to get rubidium hydroxide solutions and cesium hydroxide solutions. Subsequently, they reacted with ammonium carbonate to get rubidium carbonate and cesium carbonate. In a nutshell, this study shows the optimal parameters of pH value to precipitate potassium perchlorate. Besides, pH value in the system, the concentration of t-BAMBP and ammonia, organic phase/aqueous phase ratio (O/A ratio), reaction time, and reaction temperature in solvent extraction step were investigated to get high purities of rubidium carbonate and cesium carbonate.

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.

The effects of rubidium, caesium and quinine on 5-HT-mediated behaviour in rat and mouse--1. Rubidium

The administration of TCP (15 mg/kg, i.p.) to rats pretreated with either intraperitoneal RbCl (3 mmol/kg, twice daily for 5 days) or dietary RbCl (30 mmol/kg diet, for 14 days), resulted in the complete 5-HT behavioural syndrome. Pretreatment with p-chlorophenylalanine (i.p. 300 mg/kg x2) or (-)-propranolol (20 mg/kg, i.p.), pindolol (4 mg/kg, i.p.) and ritanserin (0.4 mg/kg, s.c.) prevented the occurrence of the 5-HT syndrome, produced by dietary RbCl plus TCP. Intraperitoneal administration of RbCl had no effect upon the 5-HT behavioural syndrome, produced by 8-OH-DPAT (0.5 mg/kg, s.c.) or 5-MeODMT (2 mg/kg, i.p.) but enhanced the 5-HT syndrome produced by quipazine (20 mg/kg, i.p.), DOI (8 mg/kg, s.c.), p-chloramphetamine (4 mg/kg, i.p.) or by TCP plus L-tryptophan (50 mg/kg, i.p.) in rats. Dietary administration of RbCl resulted in the enhancement of the 5-HT2-mediated head-twitches in the mouse and the attenuation of hypothermia in the mouse, induced by 8-OH-DPAT (0.5 mg/kg, s.c.). The accumulation of 5-HT (after inhibition of monoamine oxidase) and the rate of synthesis of 5-HT in the whole brain (minus cerebellum) were enhanced by dietary and intraperitoneal administration of RbCl, respectively. The effects of lithium and rubidium, respectively, on 5HT function in brain are compared.

A pharmacokinetic analysis of long-term administration of rubidium chloride

When a substance with a long biologic half-life is administered over an extended period with a varying dose schedule, many concerns about safety arise. In the case of rubidium chloride, which has been reported to have antidepressive activity, some of these concerns are related to the potential for unanticipated accumulation in the intracellular fluid, where replacement of more than 40% of the potassium ions is associated with toxicity in animals. A pharmacokinetic model of rubidium distribution, based on a three-compartment system, is in accord with the empirical data from previous human trials. By comparison of predicted with observed plasma rubidium levels, a sudden change in the ratio of intra- to extracellular distribution of rubidium can be detected, and availability of this warning signal of potentially toxic intracellular accumulation can be useful during extended administration.

Renal tolerance of rubidium chloride: short-term clinical evaluation

The rubidium and lithium ions are known to have opposite effects on a wide range of biochemical and behavioral parameters in experimental animals. Based on the proven effectiveness of lithium as an antimanic agent, several trials have been conducted with rubidium in the acute treatment of the depressive phase of bipolar illness. The results to date are promising. However, the 30- to 60-day biologic half-life of rubidium has mandated careful studies of potential toxicity before engaging in long-term administration of this ion to depressive subjects. One area of potential concern is the possibility of renal toxicity, which could be expressed as unexpectedly increased retention of rubidium. The data in this paper show that after 15 days of rubidium administration, there are no changes beyond the normal range in a variety of kidney function tests, including in four enzymes which are specific markers of tubule cell function.

Alternative drug therapies for mania: a literature review

This article reviews the agents used to treat manic patients. It has been suggested that up to 20 percent of all manic patients are refractory to lithium. We reviewed studies suggesting that drugs affecting the serotoninergic, adrenergic, dopaminergic, and opioid neurotransmission systems, as well as anticonvulsants and others, are possible alternative treatments. Despite the large number of agents used, few large controlled studies carefully examine these interventions. Clinical assessments using specific manic rating scales are lacking in most studies. Among the successful alternative treatments reported, carbamazepine has received the most intensive research. Other suggested therapeutic agents, such as levothyroxine and clorgyline, require additional research to verify their effectiveness. From these pharmacological approaches and an understanding of the pathophysiology of mania, future therapeutic interventions can be formulated.

Lithium, rubidium and cesium: Cerebral pharmacokinetics and alcohol interactions

The distribution of exogenously administered Li+, Rb+ and Cs+ in distinct mouse brain regions was studied as a function of time subsequent termination of a short-term daily treatment with these alkali metal salts. The resulting distribution profiles were compared with that obtained from the corresponding endogenous alkali metals. Endogenous Rb+ and Cs+ were readily measurable in all 6 brain regions studied compared to traces of measurable Li+. The Rb+ concentration was greater than that of Cs+. Short-term treatment with equal doses of the alkali metals studied showed greater brain accumulation of Rb+ and Cs+ than Li+ with a prolonged brain regions preference for Cs+ storages as a function of time. Duration of ethanol-mediated narcosis was reduced from saline controls by pretreatment with RbCl or CsCl as contrasted with prolongation by LiCl. The narcotic dosage of ethanol used reduced endogeneous Li+ and increased Cs+ levels in the cerebellum. This massive ethanol dosage exerted little effect on the distribution of exogenously administered Cs+ with exception of the striatum which continued to show a high content of Cs+. This may have contributed to partial antagonism of ethanol-depressant action and to restoring of motor function, i.e., rapid regaining of righting reflex. The results showed that Cs+ possessed longer biological life time in the brain than Rb+ or Li+ which may be of therapeutic value, i.e., in the use of Cs salts in treatment of brain tumors and in conjunction with psychoactive agents provided the respective chemotherapeutic and antidepressant properties of CsCl have been established.

Trace metals in neuropsychiatry

Naylor's recent hypothesis that vanadium ‘poisoning’ could be a factor in the severity of manic-depressive illness drew attention to the normal and even essential presence of vanadium in the diet, and in human living tissues. The whole brain may contain only about 45 micrograms of vanadium (Underwood, 1977; 1979), as against 500 micrograms of manganese, 130 μgm selenium, and less than 20 μgm molybdenum—others of the 12 or so essential metals required in traces. We might take copper as the principle trace metal—an important component of over 50 enzymes, including monoamine oxidase and dopamine β-hydroxylase—with a total in the whole man of about 100 mg. In contrast, metals like potassium (140 gm), magnesium (35 gm), iron and zinc (3–4 gm) are not present in traces but in gram quantities. Lithium, present naturally in the body in extremely minute amounts, is raised in therapy to occupy a borderline position in the scale, rather more than copper, less than zinc.

Electrolyte metabolism in patients with periodic affective disorders during treatment with rubidium

Five patients suffering from periodic affective disorders with short mood-cycles were treated with rubidium chloride, producing peak erythrocyte concentrations between 9 and 13 mmol/l. Loading with rubidium was associated with decreased total body potassium, but red-cell potassium was unchanged. Regular mood-cycling was disturbed, together with the associated body-weight changes. There was a slight extracellular "metabolic" acidosis. Electrolyte concentrations fluctuate abnormally in these patients, and two muscle biopsy specimens had very low potassium contents.

Urinary dicarboxylic acids in patients receiving lithium or rubidium salts

Lithium salts administered in therapeutic doses to four subjects who were kept on controlled diets increased up to fivefold the urinary output of some dicarboxylic acids. Some of the acids affected are intermediates in the tricarboxylic acid cycle, others are chemically similar but not directly related in metabolic terms. This is probably a direct effect on renal transport. Rubidium salts increased urinary 2-oxoglutarate output and blood 2-oxoglutarate levels, probably by some action on intermediary metabolism.

Possible mechanism of rubidium-induced hyperactivity in the rat

This study suggests that replacement of intracellular potassium by rubidium ions might lower the resting membrane potential. Thus rubidium-treated rats were more responsive to depolarizing influences and generated more cyclic AMP in the brainstem and consequently the behavioral changes.

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.