Barium toxicity and the role of the potassium inward rectifier current

Clinical features and management strategies of acute soluble barium poisoning: a review of case reports

Soluble barium salts including barium carbonate, nitrate, acetate, and chloride are commonly used in the manufacture of ceramics, insecticides, and rodenticides. Soluble barium salts are highly toxic to humans if ingested. Acute soluble barium poisoning is an uncommon but life-threatening problem. The fatal dose of barium chloride for man has been reported to be only 0.8 to 0.9 gram. Currently, there have been no systematic studies on acute soluble barium poisoning. Based on the retrospective analysis of 55 global cases, toxicological characteristics, clinical features and management of acute soluble barium poisoning were summarized. Barium is a competitive blocker of potassium inward rectifier channels to inhibit K+ efflux, resulting in profound hypokalemia. Acute soluble barium poisoning can result in gastrointestinal effects including vomiting and diarrhea, followed by hemodynamic disturbances, cardiac arrhythmias, muscle weakness, and cardiac arrest. Respiratory failure induced by muscle paralysis is the major cause of death. Management strategies mainly include prevention of barium absorption, administration of soluble sulfates, potassium supplementation, antiarrhythmic medications, hemodialysis/CVVHDF, and cardiorespiratory support. Timely administration of decontamination and correction of hypokalemia are the two important points. This narrative review will offer crucial information for treating patients with acute soluble barium poisoning.

One poison center's experience with "snake" firework ingestions

INTRODUCTION

"Snake" fireworks are a type of pyrotechnic device that, when ignited, burn and transform into a friable, snake-like structure. The inclusion of barium salts produces a green flame. Ingestion of these fireworks poses a risk of barium toxicity, which may result in hypokalemia, weakness, dysrhythmias, and respiratory distress.

METHODS

We evaluated firework-related cases at a single poison center between 2009 and 2023 and extracted those pertaining to snake fireworks. Cases were eligible for analysis if oral exposure was suspected or confirmed. Cases were excluded if there was no oral exposure, the missing firework was located after the initial call, or there was no longitudinal follow up after a suspected or witnessed exposure (that is, premature case closure). Pertinent details related to the exposure or those associated with barium toxicity were extracted and evaluated in a descriptive fashion.

RESULTS

Sixty-four cases met inclusion criteria. No deaths, dysrhythmias, weakness, or respiratory compromise were reported. All six children (9.3%) who were symptomatic had gastrointestinal complaints at initial contact with our poison center. Only two symptomatic patients had hypokalemia with the minimum serum potassium concentrations falling to 3.4 mmol/L and 2.1 mmol/L. Four additional patients developed mild hypokalemia (lowest 3.0 mmol/L) but no symptoms. The maximal latency after exposure until nadir potassium concentration was 8 h.

DISCUSSION

Oral exposures to snake fireworks occasionally resulted in mild symptomatic toxicity. The presence of symptoms did not appear to predict whether hypokalemia would develop. In the instances in which hypokalemia was present, or there was a notable downtrend in the serum potassium concentration, the repletion of potassium usually did not correlate with the extent of rebound.

CONCLUSION

In our case series, most children who had oral exposure to snake fireworks in an exploratory setting did not develop symptoms. Although severe toxicity reassuringly did not occur in our review, evaluation and monitoring are nevertheless prudent for symptomatic children.

Potassium-sensitive loss of muscle force in the setting of reduced inward rectifier K+ current: Implications for Andersen-Tawil syndrome

Andersen-Tawil syndrome (ATS) is an ion channelopathy with variable penetrance for the triad of periodic paralysis, arrhythmia, and dysmorphia. Dominant-negative mutations of KCNJ2 encoding the Kir2.1 potassium channel subunit are found in 60% of ATS families. As with most channelopathies, episodic attacks in ATS are frequently triggered by environmental stresses: exercise for periodic paralysis or stress with adrenergic stimulation for arrhythmia. Fluctuations in K+, either low or high, are potent triggers for attacks of weakness in other variants of periodic paralysis (hypokalemic periodic paralysis or hyperkalemic periodic paralysis). For ATS, the [K+] dependence is less clear; with reports describing weakness in high-K+ or low-K+. Patient trials with controlled K+ challenges are not possible, due to arrhythmias. We have developed two mouse models (genetic and pharmacologic) with reduced Kir currents, to address the question of K+-sensitive loss of force. These animal models and computational simulations both show K+-dependent weakness occurs only when Kir current is <30% of wildtype. As the Kir deficit becomes more severe, the phenotype shifts from high-K+-induced weakness to a combination where either high-K+ or low-K+ triggers weakness. A K+ channel agonist, retigabine, protects muscle from K+-sensitive weakness in our mouse models of the skeletal muscle involvement in ATS.

Exploring the Nuclearity and Structural Motifs of Phenoxyimine Alkaline Earth Complexes

The nuclearity and structural motifs of alkaline earth complexes supported by bidentate phenoxyimine ligands has been explored by modulation of the stereoelectronic profile of the ligand, the atomic number of the metal, and the synthetic protocol. Changing the size of the N-imine substituents was found to have no effect on protonolysis reactions between [MgN″2]2 or CaN″2(thf)2 (N″ = N(SiMe3)2) and H t Bu2,ArL (1-OH-2-CH = NAr-4,6- t Bu-C6H2; Ar = 2,6-iPr-C6H3 = Dipp or 2,6-CHPh2-4-Me-C6H2 = Ar*) regardless of reaction stoichiometry, with homoleptic bis(ligand) complexes ( t Bu2,DippL)2Mg (1), ( t Bu2,Ar*L)2Mg (2), ( t Bu2,DippL)2Ca(thf) (3) and ( t Bu2,Ar*L)2Ca(thf) (4) isolated. The importance of reaction protocol was demonstrated by the facile isolation of heteroleptic complex ( t Bu2,Ar*L)MgI(OEt2) (5) from the reaction of equimolar amounts of H t Bu2,Ar*L and MeMgI. Importantly, no subsequent ligand redistribution was observed when complex 5 readily reacted with KN" or KODipp to form ( t Bu2,Ar*L)Mg{N(SiMe3)2}(OEt2) (6) and ( t Bu2,Ar*L)Mg(ODipp)(thf) (7). When small 4,6-phenoxide substituents were considered (HH2,DippL), multimetallic clusters were afforded: (H2,DippL)3Ca2(N″)(thf) (8) and (H2,DippL)6Sr3 (9).

Promoting π-Facial Interactions in Phenyl-Substituted 1,8-Bis(silylamido)naphthalene Alkaline Earth Complexes

Bimetallic 1,8-bis(silylamido)naphthalene alkaline earth complexes [(R3 L)Ae]2 ([R3 L]2- = [1,8-{(R3Si)N}2C10H6)]2-, where R3 = Ph2Me, Ae = Ca (1), Sr (2), and Ba (3); R3 = Ph3, Ae = Ca (4), Sr (5), and Ba (6) were prepared via protonolysis reactions of the phenyl-substituted proligands Ph3 LH2 and Ph2MeLH2 with [AeN″2]2 (N″ = [N(SiMe3)2]-) in benzene. X-ray crystallographic analysis showed that 1, 2, and 4 crystallize as nitrogen-bridged dimers. Conversely, 5 and 6 display a naphthalene-bridged motif, while the structure of 3 is intermediate between the two distinct classes. NMR spectroscopic analysis of isolated samples of 1-6 in thf-d 8 confirmed their conversion into the monomeric thf-d 8 adducts [(R3 L)Ae(thf-d 8) n ]; crystallographic verification of the structural motif was provided by the X-ray crystal structure of [(Ph3 L)Sr(thf)3] (7). The structural range of dimers 1-6 was influenced by the electron-withdrawing nature of the phenyl substituents of the ligand and the ability to form "soft" multihaptic π-facial interactions with the metal ions, which was preferential for the larger Sr2+ and Ba2+ cations as well as the relative strength of the metal-N bonds. This has been rationalized through complementary computational studies. This work provides insight into the structure and bonding preferences of heavy alkaline earth complexes with rigid bis(amido) ligands.

Direct, rapid, non-destructive and 'white' multielemental toxicological analysis of hazardous elements with health risk assessment in candies and wrappers from Polish flea markets using portable XRF spectroscopy

Elemental analysis of solid candy and wrapper samples from Polish flea markets was conducted using portable X-ray fluorescence (pXRF), a fast, cost-effective, and non-destructive technique. Hazardous elements were detected in candies, including Ni (5.20 ± 0.56 μg/g), Fe (17.28 ± 1.03 μg/g), Ba (41.23 ± 7.10 μg/g), Cr (9.63 ± 2.30 μg/g), Cd (0.56 ± 0.33 μg/g), and Cu (7.30 ± 1.15 μg/g), while wrappers contained high levels of Ti (13073.31 ± 106.80 μg/g), Sb (158.29 ± 5.28 μg/g), and Ba (2081.01 ± 36.42 μg/g). Health risk assessments showed Ni and Cd exceeding acceptable limits, posing risks for children consuming three candies daily. Non-carcinogenic risks from Ba and Cd also surpassed provisional tolerable weekly intake (PTWI) values. Minimal migration between wrappers and candies was observed, but extreme conditions may increase contamination. The study highlights the need for stricter food safety regulations and adoption of pXRF for rapid, non-invasive detection of hazardous elements.

The First Report of Environmental Exposure to Barium in 10 Localities Close to Industrial Areas and Ports in the Amazon

Environmental exposure to metallic contaminants such as barium (Ba) is a worldwide concern, as these metals can even be toxic to the human body. Data on different sources of exposure to Ba and possible routes of entry are important for preventing adverse health effects. Blood Ba levels were evaluated in 10 localities in the cities of Barcarena and Abaetetuba in the Amazon. Ba levels were quantified using induced coupled plasma mass spectrometry, and the data were stratified per epidemiological variables and lifestyle habits. The localities were divided into two groups: Group 1, localities wherein individuals had the lowest median levels (0.299-1.330 µg·L-1), and Group 2, localities wherein individuals had the highest median levels (8740-37,300 µg·L-1). Factors such as duration of residency, sex, age, smoking status, and alcohol consumption significantly contributed to the increase in exposure. The highest concentrations were associated with drinking water sources such as underground wells and local rivers, as well as the consumption of fish. This is the first study to record Ba exposure in individuals living in localities close to the industrial areas in the Amazon. These findings may facilitate the development of new health surveillance policies and the implementation of preventive measures.

Non-fatal acute barium carbonate poisoning following suicidal ingestion: A case report

Acute barium poisoning is a rare but life-threatening method of suicide attempt, and it is a challenging disease in the emergency department. We report a case of barium carbonate poisoning in a 21-year-old man who ingested a large dose to attempt suicide and presented with gastrointestinal symptoms, gradual muscular weakness, and severe hypokalemia (K+1.63 mmol/L). He was promptly managed with gastric lavage, respiratory support, and large doses of oral and intravenous potassium supplementation. In addition, intravenous sodium thiosulfate and continuous venovenous hemodiafiltration were administered to reduce the serum concentration of barium ions. Following comprehensive treatment, the patient recovered within 5 days and discharged home for 12 days. Clinicians should be vigilant when a patient presents gastrointestinal symptoms and limb weakness, associated with severe hypokalemia and cardiac arrhythmia over a short disease course as these may indicate potential barium poisoning. Furthermore, we advocate for paying more attention to the management of toxic substances and the mental health education of young adults.

Chronic toxicity of dissolved barium and sodium chloride to the water flea Ceriodaphnia dubia: implications for unconventional gas flowback-produced waters

Unconventional gas flowback-produced waters, particularly those of marine origin from shale gas, can contain elevated concentrations of barium (Ba) and sodium chloride (NaCl). There are limited Ba water quality guideline values to help assess the potential risk of Ba exposure to freshwater biota. Barium toxicity is heavily influenced by sulfate concentrations as Ba and sulfate react, forming the highly water-insoluble and thus less bioavailable Ba sulfate. To determine survival and reproductive impacts, the water flea Ceriodaphnia dubia was exposed to dissolved Ba, NaCl, and binary combinations of dissolved Ba and NaCl. No chronic lethal concentration (LC) endpoints could be determined for dissolved Ba-only exposure up to 16 mg/L due to near 100% parent survivorship across all treatments. The NaCl LC50 (95% credible intervals) = 708 (502-939) mg/L. The dissolved Ba reproductive effect concentration (EC) at EC20 was 0.95 (0.19-3.22) mg/L. Meanwhile, for NaCl, the EC10 and EC20 concentrations were 365 (149-651) mg/L and 510 (282-760) mg/L, respectively. The binary exposure of Ba and NaCl had limited meaningful data due to some experimental shortcomings (lack of Ba-only and NaCl-only controls). Despite this, at 410 mg/L NaCl, the dissolved Ba reproductive EC10 and EC20 were determined to be 8.87 [3.58-11.7] mg/L and 10.1 (5.64-11.8) mg/L, respectively. These results suggest that marginally increased NaCl concentrations alleviate Ba toxicity, particularly when Ba is at low concentrations. Further chronic studies are needed to account for Ba toxicity in dissolved and precipitated forms and derive a Ba guideline value for freshwater biota.

Selected micro- and macro-element associations with oxidative status markers in common carp (Cyprinus carpio) blood serum and ejaculate: a correlation study

The aim of this study was to (1) determine complex interactions between macro- and micro-elements present in blood serum and ejaculate of common carp (Cyprinus carpio), and (2) examine the association between alterations in these macro- and micro-elements with markers of oxidative stress. Blood and ejaculate from 10 male carp were collected in the summer period on the experimental pond in Kolíňany (West Slovak Lowland). Reactive oxygen species (ROS), total antioxidant capacity (TAC), protein carbonyls (PC), and malondialdehyde (MDA) levels were measured in blood serum and ejaculate using spectrophotometric methods. The amounts of elements (Ag, Al, Ba, Co, Li, Mo, Ca, K, Na, and Mg) in all samples were quantified using inductively coupled plasma optical emission spectrophotometry. Data demonstrated significant differences in elemental concentrations between blood and ejaculate, specifically significantly higher ejaculate levels were detected for Ag, Al, Ba, Co, Li, Mo, K, and Mg. Potassium was the most abundant macro-element in the ejaculate, while sodium was the most abundant in blood serum. Among the micro-elements, Al was predominant in both types of samples. It is noteworthy that oxidative status markers including ROS, TAC, and MDA were significantly higher in ejaculate indicating the presence of oxidative stress in C. carpio reproductive tissue. The positive correlations between Mg and Ca in blood serum and ejaculate suggest these elements play a functional role in metabolic and physiological processes. In contrast, the positive correlations of Ba and Al with markers of oxidative stress indicated the association of these metals with induction of oxidative stress. Our findings provide insights into the association of metals with biomarkers of physiological function as well as adverse effects in C. carpio.

Trace elements exposure affects the outcomes of in vitro fertilization embryo transfer, a cohort study in Northern China

PURPOSE

With urbanization and industrialization process accelerated, humans are exposed more and more trace elements. This study aimed to explore the potential associations of trace elements with the outcomes of in vitro fertilization embryo transfer (IVF-ET).

METHODS

Total 181 women who underwent IVF-ET were enrolled, among which 89 women underwent fresh ET after IVF. Trace elements were measured in the serum and follicular fluid (FF) samples by inductively coupled plasma-mass spectroscopy. The associations of the levels of different trace elements with IVF-ET outcomes, including normal fertilization, high-quality embryos, and clinical pregnancy (fresh ET) were analyzed.

RESULTS

Twenty-five out of twenty-eight trace elements showed higher concentrations in the serum than those in the FF. Normal fertilization was positively associated with Cu and Mn in the FF. High-quality embryos was positively associated with Cu in the serum and FF, and Zn in the serum. Clinical pregnancy was positively associated with Ge in the serum, and inversely associated with Al, Ba, and Pb in the serum. Additionally, poor outcomes of IVF-ET should be noticed in women with FF level of Cu < 955.38 ng/mL, FF level of Mn < 3.42 ng/mL, serum level of Ge < 6.11 ng/mL, serum level of Al > 28.44 ng/mL, and serum level of Pb > 0.90 ng/mL.

CONCLUSIONS

IVF-ET outcomes were positively associated with Cu, Mn, Zn, and Ge, and inversely associated with Al and Pb. Properly controlling the exposure of relevant trace elements is necessary for patients with the need of IVF-ET.

The Association Between the Non-essential Metal Mixture and Handgrip Strength in Chinese Community-Dwelling Older Adults

There is limited research on the effects of non-essential metal (NEM) mixture on handgrip strength in the elderly. This study aimed to assess the associations of single NEMs and their mixture with handgrip strength in Chinese community-dwelling older adults. A total of 3807 elderly people aged 60 years or above were included in this study. Measurement of urinary aluminum (Al), arsenic (As), barium (Ba), cadmium (Cd), and gallium (Ga) concentrations was conducted by inductively coupled plasma mass spectrometry (ICP-MS). Handgrip strength was measured using a hand dynamometer. Four statistical models, including general linear regression and generalized additive models (GAMs), as well as Bayesian kernel machine regression (BKMR) and quantile-based computation regression (QGC) models, were used to assess the individual and joint effects of urine NEMs with handgrip strength, respectively. After adjusting for covariates, Ga (ß = - 0.27; 95% CI, - 0.54 ~  - 0.01) and As ( β  = - 0.34; 95% CI, - 0.61 ~  - 0.07) were negatively associated with handgrip strength. The GAMs and BKMR further suggested that the negative associations of Ga and As with handgrip strength were linear and inverted U-shaped, respectively. The BKMR and QGC models showed that the NEM mixture was negatively related to handgrip strength, with Ga and As contributing the most within the mixture. Moreover, we also observed an interaction between As and Ga on handgrip strength. Longitudinal studies are needed to verify these findings.

Rare electrocardiographic findings in a young woman with acute barium poisoning: A case report

Background

Barium, as a heavy divalent alkaline earth metal, can be found in various products such as rodenticides, insecticides, depilatories, and fireworks. Barium can be highly toxic upon both acute and chronic exposure. The toxicity of barium compounds is dependent on their solubility. Both suicidal and accidental exposures to soluble barium can cause toxicity.

Case summary

We report a case characterized by two different wide QRS complex tachycardia in a patient with acute barium poisoning, one due to barium-induced ventricular tachycardia (VT) under hypokalemia and, subsequently, sino-ventricular conduction with intraventricular conduction delay due to hyperkalemia after aggressive potassium supplementation. The latter may be misdiagnosed as VT for the history of acute barium poisoning and the absence of peaked T wave in hyperkalemia. Of note, another hemodynamically unstable VT and profound hypokalemia occurred during the potassium-lowering therapy, which, in addition to barium poisoning, may also be due to the iatrogenic hypokalemia. We also observed the prominent T-U waves at serum potassium of 4.6 mM 12 hours after admission, which may indicate that barium had not been completely cleared from the plasma at that moment. There are some parallels to the Andersen-Tawil syndrome with prominent T-U waves and risk of ventricular tachycardias. To our knowledge, this is the first case report of conversion from hypokalemia to hyperkalemia, and in a short moment, from hyperkalemia to hypokalemia, in acute barium poisoning.

Conclusion

In addition to profound hypokalemia secondary to acute barium poisoning, hyperkalemia may also occur after aggressive potassium supplementation. A more careful rather than too aggressive potassium supplementation may be suitable in these cases of hypokalemia due to an intracellular shift of potassium. And a iatrogenic hypokalemia risk in the treatment of rebound hyperkalemia in barium poisoning must be considered.

Association between Mixed Heavy Metal Exposure and Arterial Stiffness, with Alkaline Phosphatase Identified as a Mediator

Elevated arterial stiffness has been associated with exposure to heavy metals such as lead (Pb) and cadmium (Cd). However, the collective impact of multiple metals and the underlying mechanisms are not fully elucidated. The purpose of this study was to assess the combined effects of exposure to nine heavy metals on arterial stiffness and explore whether serum alkaline phosphatase (ALP) acts as a mediator in this relationship. In the retrospective analysis, data from 8,700 participants were retrieved from the National Health and Nutrition Examination Survey (NHANES) spanning from 1999 to 2018. Arterial stiffness was measured by estimated pulse wave velocity (ePWV). The cumulative impact of exposure to multiple metals was examined using adaptive elastic-net, environmental risk score, weighted quantile sum regression, and quantile g-computation. Additionally, mediation analysis was conducted to explore the potential mediating role of serum ALP. We found that combined exposure to multiple metals was consistently associated with elevated ePWV, with Ba, Pb, and Sb exhibiting the greatest contributions. Notably, serum ALP partially mediated the associations between individual (Pb, Sb) and mixed metal exposure with ePWV, with mediation proportions at 10.76% for Pb, 18.22% for Sb, and 11.07% for mixed metal exposure. In conclusion, this study demonstrates a clear association between exposure to heavy metals, either individually or in combination, and heightened arterial stiffness. Furthermore, the findings suggest that serum ALP activity may act as a mediator in these relationships.

The network of cardiac KIR2.1: its function, cellular regulation, electrical signaling, diseases and new drug avenues

The functioning of the human heart relies on complex electrical and communication systems that coordinate cardiac contractions and sustain rhythmicity. One of the key players contributing to this intricate system is the KIR2.1 potassium ion channel, which is encoded by the KCNJ2 gene. KIR2.1 channels exhibit abundant expression in both ventricular myocytes and Purkinje fibers, exerting an important role in maintaining the balance of intracellular potassium ion levels within the heart. And by stabilizing the resting membrane potential and contributing to action potential repolarization, these channels have an important role in cardiac excitability also. Either gain- or loss-of-function mutations, but also acquired impairments of their function, are implicated in the pathogenesis of diverse types of cardiac arrhythmias. In this review, we aim to elucidate the system functions of KIR2.1 channels related to cellular electrical signaling, communication, and their contributions to cardiovascular disease. Based on this knowledge, we will discuss existing and new pharmacological avenues to modulate their function.

A Systematic Literature Review on the Association Between Toxic and Essential Trace Elements and the Risk of Orofacial Clefts in Infants

Orofacial clefts (OFCs) have been linked to various toxic and essential trace elements (TETEs) worldwide. However, review estimation is absent. Therefore, addressing the hypothesis that TETEs are associated with OFCs is the main area of this review. A systematic literature search was conducted using electronic databases through PubMed, Web of Science, Scopus, Science Direct, and Google Scholar between 2004 and August 2022. The "AND" and "OR" operators were used to make our search results inclusive and restrictive as follows: ("Toxic element*" OR "Heavy metal*") AND ("Toxic element*" OR "Lead OR Arsenic OR Mercury*")) AND ("Essential trace element*" OR "Zinc OR Selenium OR Copper*")) AND ("Orofacial cleft*" OR "Cleft lip*" OR "Cleft palate*") AND ("Infant*" OR "Newborn*" OR "Neonate*")). The presence of toxic elements was linked to the development of OFCs. The results showed that higher levels of toxic elements in various biological sample types were related to increased risks for OFCs. Increased concentrations of essential trace elements (ETEs) lowered the risk of OFCs. Maternal consumption of diets rich in ETEs, including zinc (Zn), selenium (Se), copper (Cu), cobalt (Co), and molybdenum (Mo), was linked to a more pronounced reduction in the risk of OFCs. Based on the findings, it is acceptable to infer that maternal exposure to toxic elements, whether through environmental contaminants or dietary sources, was associated with an elevated risk of OFCs. Furthermore, the study revealed that ETEs exhibited a potential protective role in reducing the incidence of OFCs. This observation highlights the importance of reducing exposure to toxic elements during pregnancy and suggests that optimizing maternal intake of ETEs could be an effective preventive strategy.

The Utrecht University Honours Program review project: example based scientific publishing training aimed at bachelor medical students

INTRODUCTION

Medical undergraduate students receive limited education on scholarly publishing. However, publishing experiences during this phase are known to influence study and career paths. The medical bachelor Honours Program (HP) at Utrecht University initiated a hands-on writing and publishing course, which resulted in nine reviews published in internationally peer reviewed academic journals. We wanted to share the project set-up, explore the academic development of the participating students and determine the impact of the reviews on the scientific community.

METHODS

Thirty-one out of 50 alumni completed a digital retrospective questionnaire on for example, development of skills and benefit for their studies and career. Publication metrics of the HP review papers were retrieved from Web of Science.

RESULTS

This hands-on project provides a clear teaching method on academic writing and scholarly publishing in the bachelor medical curriculum. Participants were able to obtain and improve writing and publishing skills. The output yielded well-recognized scientific papers and valuable learning experiences. 71% of the participating students published at least one additional paper following this project, and 55% of the students indicated the project influenced their academic study and/or career path. Nine manuscripts were published in journals with an average impact factor of 3.56 and cited on average 3.73 times per year.

DISCUSSION

This course might inspire other medical educators to incorporate similar projects successfully into their curriculum. To this end, a number of recommendations with regard to supervision, time investment and group size are given.

Subchronic pulmonary toxicity of ambient particles containing cement production-related elements

Chronic respiratory disease is among the most common non-communicable diseases, and particulate materials (PM) are a major risk factor. Meanwhile, evidence of the relationship between the physicochemical characteristics of PM and pulmonary toxicity mechanism is still limited. Here, we collected particles (CPM) from the air of a port city adjacent to a cement factory, and we found that the CPM contained various elements, including heavy metals (such as arsenic, thallium, barium, and zirconium) which are predicted to have originated from a cement plant adjacent to the sampling site. We also delivered the CPM intratracheally to mice for 13 weeks to investigate the pulmonary toxicity of inhaled CPM. CPM-induced chronic inflammatory lesions with an increased total number of cells in the lung of mice. Meanwhile, among inflammatory mediators measured in this study, levels of IL-1β, TNF-α, CXCL-1, and IFN-γ were elevated in the treated group compared with the controls. Considering that the alveolar macrophage (known as dust cell) is a professional phagocyte that is responsible for the clearance of PM from the respiratory surfaces, we also investigated cellular responses following exposure to CPM in MH-S cells, a mouse alveolar macrophage cell line. CPM inhibited cell proliferation and formed autophagosome-like vacuoles. Intracellular calcium accumulation and oxidative stress, and altered expression of pyrimidine metabolism- and olfactory transduction-related genes were observed in CPM-treated cells. More interestingly, type I-LC3B and full-length PARP proteins were not replenished in CPM-treated cells, and cell cycle changes, apoptotic and necrotic cell death, and caspase-3 cleavage were not significantly detected in cells exposed to CPM. Taken together, we conclude that dysfunction of alveolar macrophages may contribute to CPM-induced pulmonary inflammation. In addition, given the possible transformation of heart tissue observed in CPM-treated mice, we suggest that further study is needed to clarify the systemic pathological changes and the molecular mechanisms following chronic exposure to CPM.

Contaminant Metals and Cardiovascular Health

A growing body of research has begun to link exposure to environmental contaminants, such as heavy metals, with a variety of negative health outcomes. In this paper, we sought to review the current research describing the impact of certain common contaminant metals on cardiovascular (CV) health. We reviewed ten metals: lead, barium, nickel, chromium, cadmium, arsenic, mercury, selenium, zinc, and copper. After a literature review, we briefly summarized the routes of environmental exposure, pathophysiological mechanisms, CV health impacts, and exposure prevention and/or mitigation strategies for each metal. The resulting article discloses a broad spectrum of pathological significance, from relatively benign substances with little to no described effects on CV health, such as chromium and selenium, to substances with a wide-ranging and relatively severe spectrum of CV pathologies, such as arsenic, cadmium, and lead. It is our hope that this article will provide clinicians with a practical overview of the impact of these common environmental contaminants on CV health as well as highlight areas that require further investigation to better understand how these metals impact the incidence and progression of CV diseases.

Heavy metal deposition and parameter change of soft contact lenses by exposure to particulate matter : Parameter change of SCL due to exposure to PM and heavy metal deposition

BACKGROUND

Particulate matter (PM) is known to contain heavy metals and be harmful to the tissues and organs of the human body including the eyes. As such, in this study, the deposition of heavy metals from PM on soft contact lenses was examined, and changes in the lens parameters were further investigated.

METHODS

Six types of soft contact lenses were exposed to captured PM10 for eight hours. The central thickness, water content, refractive power, and oxygen transmissibility of each contact lens were measured after analyzing the amounts of six heavy metals adsorbed on the contact lenses.

RESULTS

Lead, manganese, barium, arsenic, vanadium, and cadmium were detected in the captured PM, and only lead was adsorbed on all soft contact lenses except senofilcon C. The largest deposition was 23.21 ± 0.70 (10- 3)µg/lens of the lead on lotrafilcon B. The oxygen transmissibility of nelfilcon A exhibited statistically significant changes, however, it was within the ISO standard tolerance. Nevertheless, changes in the central thickness, water content, and refractive power of each soft contact lens were not statistically significant.

CONCLUSIONS

This study revealed that a considerable amount of lead in PM10 was adsorbed on soft contact lenses. Amongst lens parameters, only oxygen transmissibility changed significantly. Thus, wearing soft contact lenses under high PM10 concentration might affect the physiology of the eyes.

A State-of-the-Science Review on Metal Biomarkers

PURPOSE OF REVIEW

Biomarkers are commonly used in epidemiological studies to assess metals and metalloid exposure and estimate internal dose, as they integrate multiple sources and routes of exposure. Researchers are increasingly using multi-metal panels and innovative statistical methods to understand how exposure to real-world metal mixtures affects human health. Metals have both common and unique sources and routes of exposure, as well as biotransformation and elimination pathways. The development of multi-element analytical technology allows researchers to examine a broad spectrum of metals in their studies; however, their interpretation is complex as they can reflect different windows of exposure and several biomarkers have critical limitations. This review elaborates on more than 500 scientific publications to discuss major sources of exposure, biotransformation and elimination, and biomarkers of exposure and internal dose for 12 metals/metalloids, including 8 non-essential elements (arsenic, barium, cadmium, lead, mercury, nickel, tin, uranium) and 4 essential elements (manganese, molybdenum, selenium, and zinc) commonly used in multi-element analyses.

RECENT FINDINGS

We conclude that not all metal biomarkers are adequate measures of exposure and that understanding the metabolic biotransformation and elimination of metals is key to metal biomarker interpretation. For example, whole blood is a good biomarker of exposure to arsenic, cadmium, lead, mercury, and tin, but it is not a good indicator for barium, nickel, and uranium. For some essential metals, the interpretation of whole blood biomarkers is unclear. Urine is the most commonly used biomarker of exposure across metals but it should not be used to assess lead exposure. Essential metals such as zinc and manganese are tightly regulated by homeostatic processes; thus, elevated levels in urine may reflect body loss and metabolic processes rather than excess exposure. Total urinary arsenic may reflect exposure to both organic and inorganic arsenic, thus, arsenic speciation and adjustment for arsebonetaine are needed in populations with dietary seafood consumption. Hair and nails primarily reflect exposure to organic mercury, except in populations exposed to high levels of inorganic mercury such as in occupational and environmental settings. When selecting biomarkers, it is also critical to consider the exposure window of interest. Most populations are chronically exposed to metals in the low-to-moderate range, yet many biomarkers reflect recent exposures. Toenails are emerging biomarkers in this regard. They are reliable biomarkers of long-term exposure for arsenic, mercury, manganese, and selenium. However, more research is needed to understand the role of nails as a biomarker of exposure to other metals. Similarly, teeth are increasingly used to assess lifelong exposures to several essential and non-essential metals such as lead, including during the prenatal window. As metals epidemiology moves towards embracing a multi-metal/mixtures approach and expanding metal panels to include less commonly studied metals, it is important for researchers to have a strong knowledge base about the metal biomarkers included in their research. This review aims to aid metals researchers in their analysis planning, facilitate sound analytical decision-making, as well as appropriate understanding and interpretation of results.

Subway station dust-induced pulmonary inflammation may be due to the dysfunction of alveolar macrophages: Possible contribution of bound elements

With its increasing value as a means of public transportation, the health effects of the air in subway stations have attracted public concern. In the current study, we investigated the pulmonary toxicity of dust collected from an air purifier installed on the platform of the busiest subway station in Seoul. We found that the dust contained various elements which are attributable to the facilities and equipment used to operate the subway system. Particularly, iron (Fe), chromium (Cr), zirconium (Zr), barium (Ba), and molybdenum (Mo) levels were more notable in comparison with those in dust collected from the ventilation chamber of a subway station. To explore the health effects of inhaled dust, we first instilled via the trachea in ICR mice for 13 weeks. The total number of pulmonary macrophages increased significantly with the dose, accompanying hematological changes. Dust-laden alveolar macrophages and inflammatory cells accumulated in the perivascular regions in the lungs of the treated mice, and pulmonary levels of CXCL-1, TNF-α, and TGF-β increased clearly compared with the control. The CCR5 and CD54 level expressed on BAL cell membranes was also enhanced following exposure to dust, whereas the CXCR2 level tended to decrease in the same samples. In addition, we treated the dust to alveolar macrophages (known as dust cells), lysosomal and mitochondrial function decreased, accompanied by cell death, and NO production was rapidly elevated with concentration. Moreover, the expression of autophagy- (p62) and anti-oxidant (SOD-2)-related proteins increased, and the expression of inflammation-related genes was dramatically up-regulated in the dust-treated cells. Therefore, we suggest that dysfunction of alveolar macrophages may importantly contribute to dust-induced inflammatory responses and that the exposure concentrations of Cr, Fe, Mo, Zr, and Ba should be considered carefully when assessing the health risks associated with subway dust. We also hypothesize that the bound elements may contribute to dust-induced macrophage dysfunction by inhibiting viability.

Serum potassium changes during hypothermia and rewarming: a case series and hypothesis on the mechanism

Introduction

Hypokalemia is known to occur in association with therapeutically induced hypothermia and is usually managed by the administration of potassium (K+).

Methods

We reviewed data from 74 patients who underwent a therapeutic hypothermia protocol at our medical institution.

Results

In four patients in whom data on serum K+ and temperature were available, a strong positive correlation between serum K+ and body temperature was found. Based on the close positive relationship between serum K+ and total body temperature, we hypothesize that serum K+ decreases during hypothermia owing to decreased activity of temperature-dependent K+ exit channels that under normal conditions are sufficiently active to match cellular K+ intake via sodium/K+/adenosine triphosphatase. Upon rewarming, reactivation of these channels results in a rapid increase in serum K+ as a result of K+ exit down its concentration gradient.

Conclusion

Administration of K+ during hypothermia should be done cautiously and avoided during rewarming to avoid potentially life-threatening hyperkalemia. K+ exit via temperature-dependent K+ channels provides a logical explanation for the rebound hyperkalemia. K+ exit channels may play a bigger role than previously appreciated in the regulation of serum K+ during normal and pathophysiological conditions.

Characterization of childhood exposure to environmental contaminants using stool in a semi-urban middle-class cohort from eastern Canada

Children are exposed to various environmental organic and inorganic contaminants with effects on health outcomes still largely unknown. Many matrices (e.g., blood, urine, nail, hair) have been used to characterize exposure to organic and inorganic contaminants. The sampling of feces presents several advantages; it is non-invasive and provides a direct evaluation of the gut microbiome exposure to contaminants. The gut microbiome is a key factor in neurological development through the brain-gut axis. Its composition and disturbances can affect the neurodevelopment of children. Characterization of children exposure to contaminants is often performed on vulnerable populations (e.g., from developing countries, low-income neighborhoods, and large urban centers). Data on the exposure of children from middle-class, semi-urban, and mid-size populations to contaminants is scarce despite representing a significant fraction of the population in North America. In this study, 73 organics compounds from different chemical classes and 22 elements were analyzed in 6 years old (n = 84) and 10 years old (n = 119) children's feces from a middle-class, semi-urban, mid-size population cohort from Eastern Canada. Results show that 67 out of 73 targeted organics compounds and all elements were at least detected in one child's feces. Only caffeine (97% & 80%) and acetaminophen (28% & 48%) were detected in more than 25% of the children's feces, whereas all elements besides titanium were detected in more than 50% of the children.

A Fatal Case Report of Barium Chloride Toxicity

Barium is an alkaline earth metal whose toxicity is dictated by its compounded salt form: barium sulfate is insoluble and safe to ingest, but other barium salts (chloride, carbonate, sulfide, oxide and acetate) are bioavailable and therefore toxic when ingested. There have been 49 previous reports of fatal intoxications following barium consumption: 38 deemed accidental in nature, 8 suicidal, 1 homicidal and 2 of undetermined intent. In this report, we detail the first intentional fatal self-poisoning with barium chloride to be reported in the UK, along with a review of the surrounding literature. This is the first case to report quantified levels of barium in blood and vitreous humor, and by providing details of sample collection, storage and processing, this case will aid in future interpretations.

Exposure to essential and non-essential trace elements and risks of congenital heart defects: A narrative review

Congenital heart defects (CHDs) are congenital abnormalities involving the gross structures of the heart and large blood vessels. Environmental factors, genetic factors and their interactions may contribute to the pathogenesis of CHDs. Generally, trace elements can be classified into essential trace elements and non-essential trace elements. Essential trace elements such as copper (Cu), zinc (Zn), iron (Fe), selenium (Se), and manganese (Mn) play important roles in human biological functions such as metabolic function, oxidative stress regulation, and embryonic development. Non-essential trace elements such as cadmium (Cd), arsenic (As), lead (Pb), nickle (Ni), barium (Ba), chromium (Cr) and mercury (Hg) are harmful to health even at low concentrations. Recent studies have revealed the potential involvement of these trace elements in the pathogenesis of CHDs. In this review, we summarized current studies exploring exposure to essential and non-essential trace elements and risks of CHDs, in order to provide further insights for the pathogenesis and prevention of CHDs.

Seasonal variation, contribution and dynamics of trace elements in the drainage basin and estuary of the Serinhaém river, BA

In the present study a mass balance calculation was used to quantify trace elements (Al, Ba, Cd, Cr, Cu, Fe, Mn, Pb, Ti, V and Zn) fluxes exported from the Serinhaém River estuary to the Atlantic Ocean. The studied elements exportation in the particulate fraction showed higher fluxes in the first sampling campaign and a high export rate to the Atlantic Ocean during this period. The physical-chemical parameters showed the highest values in sampling campaign 1. These variations are probably the cause of the different trace elements behavior in fluvial and estuarine areas, where removal and addition processes between particulate and dissolved phases took place, affecting distribution coefficient and fluxes to the Atlantic Ocean. EPA ecosystems present values in accordance with Brazilian legislation for pristine areas, however, monitoring programs must be carried out in the region, to avoid future environmental problems.

Massive Accumulation of Strontium and Barium in Diplonemid Protists

Barium and strontium are often used as proxies of marine productivity in palaeoceanographic reconstructions of global climate. However, long-searched biological drivers for such correlations remain unknown. Here, we report that taxa within one of the most abundant groups of marine planktonic protists, diplonemids (Euglenozoa), are potent accumulators of intracellular barite (BaSO₄), celestite (SrSO₄), and strontiobarite (Ba,Sr)SO₄. In culture, Namystinia karyoxenos accumulates Ba²⁺ and Sr²⁺ 42,000 and 10,000 times higher than the surrounding medium, forming barite and celestite representing 90% of the dry weight, the greatest concentration in biomass known to date. As heterotrophs, diplonemids are not restricted to the photic zone, and they are widespread in the oceans in astonishing abundance and diversity, as their distribution correlates with environmental particulate barite and celestite, prevailing in the mesopelagic zone. We found diplonemid predators, the filter-feeding zooplankton that produces fecal pellets containing the undigested celestite from diplonemids, facilitating its deposition on the seafloor. To the best of our knowledge, evidence for diplonemid biomineralization presents the strongest explanation for the occurrence of particulate barite and celestite in the marine environment. Both structures of the crystals and their variable chemical compositions found in diplonemids fit the properties of environmentally sampled particulate barite and celestite. Finally, we propose that diplonemids, which emerged during the Neoproterozoic era, qualify as impactful players in Ba²⁺/Sr²⁺ cycling in the ocean that has possibly contributed to sedimentary rock formation over long geological periods. IMPORTANCE We have identified that diplonemids, an abundant group of marine planktonic protists, accumulate conspicuous amounts of Sr²⁺ and Ba²⁺ in the form of intracellular barite and celestite crystals, in concentrations that greatly exceed those of the most efficient Ba/Sr-accumulating organisms known to date. We propose that diplonemids are potential players in Ba²⁺/Sr²⁺ cycling in the ocean and have possibly contributed to sedimentary rock formation over long geological periods. These organisms emerged during the Neoproterozoic era (590 to 900 million years ago), prior to known coccolithophore carbonate biomineralization (~200 million years ago). Based on reported data, the distribution of diplonemids in the oceans is correlated with the occurrence of particulate barite and celestite. Finally, diplonemids may provide new insights into the long-questioned biogenic origin of particulate barite and celestite and bring more understanding of the observed spatial-temporal correlation of the minerals with marine productivity used in reconstructions of past global climate.

The Gilded Clot: Review of Metal-Modulated Platelet Activation, Coagulation, and Fibrinolysis

The processes of blood coagulation and fibrinolysis that in part maintain the physical integrity of the circulatory system and fluidity of its contents are complex as they are critical for life. While the roles played by cellular components and circulating proteins in coagulation and fibrinolysis are widely acknowledged, the impact of metals on these processes is at best underappreciated. In this narrative review we identify twenty-five metals that can modulate the activity of platelets, plasmatic coagulation, and fibrinolysis as determined by in vitro and in vivo investigations involving several species besides human beings. When possible, the molecular interactions of the various metals with key cells and proteins of the hemostatic system were identified and displayed in detail. It is our intention that this work serve not as an ending point, but rather as a fair evaluation of what mechanisms concerning metal interactions with the hemostatic system have been elucidated, and as a beacon to guide future investigation.

Mixture Toxicity of Three Unconventional Gas Fracking Chemicals, Barium, O-Cresol, and Sodium Chloride, to the Freshwater Shrimp Paratya australiensis

The 96-h acute toxicity of barium (Ba²⁺ ), o-cresol, and sodium chloride (NaCl) to Paratya australiensis was assessed in single, binary, and ternary combinations in addition to three biochemical assays: glutathione S-transferase, acetylcholinesterase, and sodium-potassium adenosine triphosphatase. The 96-h lethal concentrations that expressed 50% mortality (LC50) in the single-toxicant exposures were Ba²⁺  = 23.4 mg/L, o-cresol = 12.2 mg/L, and NaCl = 4198 mg/L. Mortality from o-cresol exposure occurred between 11 and 22 mg/L, whereas Ba²⁺ was more gradual across 10-105 mg/L, and most of the NaCl mortality occurred between 2050 and 4100 mg/L. Toxic units were used to assess the binary and ternary interactions of the toxicants. A more than additive effect was observed for most combinations in the binary chemical exposures, with the ternary combinations yielding highly synergistic interactions. Greater synergism was observed with the 96-h LC50 of o-cresol in combination with the three concentrations of NaCl (1025, 2050, and 3075 mg/L) compared with Ba²⁺ , with toxic units of 0.38, 0.48, and 0.10 (o-cresol) and 0.71, 0.67, and 0.50 (Ba²⁺ ). No notable enzyme activity trends were observed in the enzyme biomarker responses from both individual and mixture exposures. Although acute single-species toxicity tests tend to underestimate the effects of Ba²⁺ , o-cresol, and NaCl on populations, communities, and ecosystems in seminatural (e.g., mesocosms) and natural systems, there are currently no published acute toxicity data available for P. australiensis and the three toxicants used in the present study. The present study shows that chemicals with different toxicity mechanisms can potentially lead to more synergistic responses. Environ Toxicol Chem 2023;42:481-494. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Heavy metals research in Nigeria: a review of studies and prioritization of research needs

Nigeria is experiencing continuous economic and industrial transformations, typical of many developing nations. In addition to its well-established oil industry, which is infamous for exuding various kinds of pollutants, there are increased mining operations, indiscriminate disposal and burning of wastes, illegal oil refinery and terroristic insurgency, all poised to increase the levels of heavy metal contaminants in the Nigerian environment. A recent revelation indicates that about 2 million people in South-western Nigeria alone could potentially be poisoned by lead (Pb) and mercury (Hg), emanating from illegal mining operations. This further underscores the importance of investigations of toxic trace metal levels in the country. The current review of 148 research articles was conducted to provide an understanding of the scope of heavy metals research in Nigeria and to prioritize needed research. The review recognized that the scope of heavy metals studies has been wide, covering matrices such as cosmetics, human blood, hair, medicines, foods, beverages, water, air, soil and crude oil. However, important toxic metals, especially mercury (Hg), arsenic (As) and antimony (Sb), are largely under-investigated. Also, there is a need for more studies to be conducted in the northern part of the country. Furthermore, studies need to focus on marine environments rather than the freshwater ecosystems alone. Techniques such as the inductively coupled plasma-optical emission spectrometry (ICP-OES) and particle-induced X-ray emission (PIXE) analyses are herein recommended to bridge the data gap and to overcome limitations in trace metals analyses in the Nigerian total environment.

Assessment of physical and chemical properties, health risk of trace metals and quality indices of surface waters of the rivers and lakes of the Kola Peninsula (Murmansk Region, North-West Russia)

The pollution of waterbodies with trace metals is of concern throughout the world due to their high toxicity. One of the main anthropogenic sources of trace metals entering natural waters is the mining and processing of minerals. Intensive development of the mining industry on the Kola Peninsula (the Murmansk region, Russia), exploration and development of new mineral resources have led to a sharp deterioration in the quality of surface waters of rivers and lakes. As a result of anthropogenic impact, accumulation of a wide range of metals (mainly Cu, Ni, Co, Pb, Cd, Mn, Sr, Al and Fe) is observed, as well as significant changes in the physicochemical parameters and radioactive conditions of surface waters. The most polluted waterbodies of the Kola Peninsula are located in the Monchegorsk, Olenegorsk and Apatit regions. Consumption of water from investigated contaminated sources can cause various high risks of human health. The results of this study will provide an informative basis for future risk assessments of the environment and human health, as well as for the development of integrated measures for managing the quality of surface waters of lakes and rivers of the Kola Peninsula.

Potassium Derangements: A Pathophysiological Review, Diagnostic Approach, and Clinical Management

Potassium is an essential cation critical in fluid and electrolyte balance, acid–base regulation, and neuromuscular functions. The normal serum potassium is kept within a narrow range of 3.5–5.2 meq/L while the intracellular concentration is approximately 140–150 meq/L. The total body potassium is about 45–55 mmol/kg; thus, a 70 kg male has an estimated ~136 g and 60 kg female has ~117 g of potassium. In total, 98% of the total body potassium is intracellular. Skeletal muscle contains ~80% of body potassium stores. The ratio of intracellular to extracellular potassium concentration (Ki/Ke) maintained by Na+/K+ ATPase determines the resting membrane potential. Disturbances of potassium homeostasis lead to hypo- and hyperkalemia, which if severe, can be life-threatening. Prompt diagnosis and management of these problems are important.

Levels of leachable elements from long-term use of enFlow fluid warmer

Objective:

In the delivery of intravenous fluids, in-line warming devices frequently transfer heat using a metal heating plate, which if uncoated can risk elution. This bench study examined extractable elements detected following long-term use of the parylene-coated enFlow^® Disposable IV/Blood Warmer.

Methods:

We tested 16 clinically relevant challenge fluids typical of the surgical setting, including commercially available single donor blood and blood products as well as intravenous saline and electrolyte solutions. After 72 h of warming at 40°C (104°F) via the enFlow, analytical chemistry identified and quantified the most clinically significant extractable elements (arsenic, barium, cadmium, copper, and lead) to estimate chemical exposure. We also measured the extracted concentrations of these five elements following simulated use of the device with three solutions (Sterofundin ISO, Plasma-Lyte 148, and whole blood) that were pumped through the warmed device at two different flow rates (0.2 and 5.5 mL min⁻¹).

Results:

Across all scenarios of acute and long-term exposures for different populations, the enFlow demonstrated low toxicological risks as measured by the calculation of tolerable exposure for extracted arsenic, barium, cadmium, copper, and lead.

Conclusion:

The results suggest biological safety for the use of parylene-coated enFlow with a variety of intravenous solutions and in different therapeutic scenarios.

Life-threatening barium carbonate poisoning managed with intravenous potassium, continuous veno-venous haemodialysis and endoscopic removal of retained ceramic glazes

INTRODUCTION

Barium poisoning is rare but potentially severe. We describe a case of acute barium carbonate poisoning with cardiac arrest, managed with intravenous potassium, dialysis and endoscopic removal of retained ceramic glazes.

CASE REPORT

A 38-year-old woman presented with vomiting 90 min after ingesting 3 cups of barium and strontium carbonate. Initial bloods noted potassium 2.8 mmol/L and creatinine 53 μmol/L. Electrocardiogram demonstrated prolonged corrected QT interval 585msec. Initial management included intravenous potassium. Four hours post-ingestion she developed proximal muscle weakness in upper limbs with a potassium of 2.2 mmol/L. At 15 h post-ingestion she developed profound muscle weakness, polymorphic ventricular tachycardia and cardiac arrest. Treatment included defibrillation, endotracheal intubation and continuous veno-venous haemodialysis (CVVHD) for metabolic derangement and enhanced elimination of barium. Chest X-ray 17 h post-ingestion demonstrated a large radio-opaque mass in the stomach, thought to be the ceramic glaze. Endoscopy removed the retained material 41 h post-ingestion. She was extubated 58 h post-ingestion and CVVHD was ceased on day 3. Serum creatinine peaked at 348 μmol/L on day 7, but normalised by discharge. Biphasic barium concentrations were noted, notably 94 μmol/L on admission, 195 μmol/L at 16 h, 95 μmol/L at 20 h, and 193 μmol/L at 30 h post-ingestion.

CONCLUSION

In barium poisoning with hypokalaemia, prompt potassium supplementation is required but rebound hyperkalaemia can occur. Endoscopic removal of ceramic glazes may be useful more than 12 h post-ingestion. Consider extracorporeal methods to enhance barium elimination in severe cases.

Combination of Sildenafil and Ba2+ at a Low Concentration Show a Significant Synergistic Inhibition of Inward Rectifier Potassium Current Resulting in Action Potential Prolongation

Sildenafil (Viagra) is a vasodilator mainly used in the treatment of erectile dysfunction. Atrial or ventricular fibrillation may rarely occur as a side effect during sildenafil therapy. Although changes in inward rectifier potassium currents including I_K1 are known to contribute to the pathogenesis of fibrillation, the effect of sildenafil on I_K1 has not been studied. In experiments, Ba²⁺ is used as a specific inhibitor of I_K1 at high concentrations (usually 100 µM). Being an environmental contaminant, it is also present in the human body; Ba²⁺ plasmatic concentrations up to 1.5 µM are usually reported in the general population. This study was primarily aimed to investigate changes of I_K1 induced by sildenafil in a wide range of concentrations (0.1–100 µM). Additionally, the effect of combination of sildenafil and Ba²⁺ at selected clinically-relevant concentrations was tested, at 0.1 µM both on I_K1 and on the action potential duration (APD). Experiments were performed by the whole-cell patch-clamp technique on enzymatically isolated rat ventricular cardiomyocytes, mostly at 23°C with the exception of APD measurements which were performed at 37°C as well. Sildenafil caused a significant, reversible, and concentration-dependent inhibition of I_K1 that did not differ at −50 and −110 mV. Simultaneous application of sildenafil and Ba²⁺ at 0.1 µM revealed a massive inhibition of both inward and outward components of I_K1 (this synergy was missing at other tested combinations). The combined effect at 0.1 µM (45.7 ± 5.7 and 43.0 ± 6.9% inhibition at −50 and −110 mV, respectively) was significantly higher than a simple sum of almost negligible effects of the individual substances and it led to a significant prolongation of APD at both 23 and 37°C. To our knowledge, similar potentiation of the drug-channel interaction has not been described. The observed massive inhibition of I_K1 induced by a combined action of the vasodilator sildenafil and environmental contaminant Ba²⁺ at a low concentration and resulting in a significant APD prolongation may contribute to the genesis of arrhythmias observed in some patients treated with sildenafil.

Transcriptomics changes and the candidate pathway in human macrophages induced by different PM2.5 extracts

Ambient fine particulate matter (PM_2.5) is a worldwide environmental problem and is posing a serious threat to human health. Until now, the molecular toxicological mechanisms and the crucial toxic components of PM_2.5 remain to be clarified. This study investigated the whole transcriptomic changes in THP-1 derived macrophages treated with different types of PM_2.5 extracts using RNA sequencing technique. Bioinformatics analyses covering biological functions, signal pathways, protein networks and node genes were performed to explore the candidate pathways and critical genes, and to find the potential molecular mechanisms. Results of Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes pathway (KEGG), and protein-protein interaction (PPI) networks revealed that water extracts (WEs) of PM_2.5 obviously influenced genes and molecular pathways responded to oxidative stress and inflammation. Dichloromethane extracts (DEs) specifically affected genes and signal cascades related to cell cycle progress process. Furthermore, compared with WEs collected in heating season, non-heating season WEs induced much higher expression levels of Ca-associated genes (including phosphodiesterase 4B and cyclooxygenase-2), which may consequently result in more severe inflammatory responses. While, for DEs exposure, the heating season (DH) group showed extensive induction of deferentially expressed genes (DEGs) related to cell cycle pathway, which may be caused by the higher polycyclic aromatic hydrocarbons (PAHs) contents in DH samples than those from non-heating season. In conclusion, the oxidative stress and inflammation response are closely correlated with cellular responses in THP-1 derived macrophages induced by water soluble components of PM_2.5, and cell cycle dysregulation may play an important role in biological effects induced by organic components. The different transcriptomic changes induced by seasonal PM_2.5 extracts may partially depend on the contents of PAHs and metal ions, respectively.

Metal peroxides for cancer treatment

In recent years, metal peroxide (MO2) such as CaO2 has received more and more attention in cancer treatment. MO2 is readily decompose to release metal ions and hydrogen peroxide in the acidic tumor microenvironment (TME), resulting metal ions overloading, decreased acidity and elevated oxidative stress in TME. All of these changes making MO2 an excellent tumor therapeutic agent. Moreover, by combining MO2 with photosensitizers, enzymes or Fenton reagents, MO2 can assist and promote various tumor therapies such as photodynamic therapy and chemodynamic therapy. In this review, the synthesis and modification methods of MO2 are introduced, and the representative studies of MO2-based tumor monotherapy and combination therapy are discussed in detail. Finally, the current challenges and prospects of MO2 in the field of tumor therapy are emphasized to promote the development of MO2-based cancer treatment.

Environmental barium: potential exposure and health-hazards

The relatively widespread presence of environmental barium is raising a growing public awareness as it can lead to different health conditions. Its presence in humans may produce several effects, especially among those chronically exposed from low to moderate doses. Barium accumulation can mainly occur by exposure in the workplace or from drinking contaminated water. However, this element is also assumed with the diet, mainly from plant foods. The average amount of barium intake worldwide and its geographical variation is little known due to the lack of research attention. Barium was never considered as an essential nutrient for humans, although it is undoubtedly naturally abundant enough and distinctive in its chemical properties that it might well have some biochemical function, e.g., for regulatory purposes, both in animals and plants. The information on the potential health effects of barium exposure is primarily based on animal studies and reported as comprising kidney diseases, neurological, cardiovascular, mental, and metabolic disorders. The present paper considers exposure and potential health concerns on environmental barium, giving evidence to information that can be used in future epidemiological and experimental studies.

Evaluation of La(XT), a novel lanthanide compound, in an OVX rat model of osteoporosis

Purpose

The purpose of this study was to evaluate the efficacy and toxicity of a novel lanthanum compound, La(XT), in an ovariectomized (OVX) rat model of osteoporosis.

Methods

Twenty-four ovariectomized female Sprague Dawley rats were divided into 3 groups receiving a research diet with/without treatment compounds (alendronate: 3 mg/kg; La(XT) 100 mg/kg) for three months. At the time of sacrifice, the kidney, liver, brain, lung and spleen were collected for histological examination. The trabecular bone structure of the tibiae was evaluated using micro-CT and a three-point metaphyseal mechanical test was used to evaluate bone failure load and stiffness.

Results

No significant differences were noted in plasma levels of calcium, phosphorus, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) between the La(XT) treatment compared to the non-treated OVX group. Alendronate-treated animals (positive control) showed higher BV/TV, Tb.N and lower Tb.Th and Tb.Sp when compared to the non-treated OVX group. Mechanical analysis indicated that stiffness was higher in the alendronate (32.88%, p = 0.04) when compared to the non-treated OVX group. Failure load did not differ among the groups.

Conclusions

No kidney or liver toxicities of La(XT) treatments were found during the three-month study. The absence of liver and kidney toxicity with drug treatment for 3 months, as well as the increased trabecular bone stiffness are encouraging for the pursuit of further studies with La(XT) for a longer duration of time.

Sulfur supply reduces barium toxicity in Tanzania guinea grass (Panicum maximum) by inducing antioxidant enzymes and proline metabolism

Sulfur (S) can play essential roles in protecting plants against abiotic stress, including heavy metal toxicity. However, the effect of this nutrient on plants exposed to barium (Ba) is still unknown. This study was designed to evaluate the S supply on oxidative stress and the antioxidant system of Tanzania guinea grass under exposure to Ba, grown in a nutrient solution under greenhouse conditions. It was studied the influence of S/Ba combinations in nutrient solution on oxidative stress indicators (hydrogen peroxide, malondialdehyde, and proline) and antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase). The treatments consisted in thirteen S/Ba combinations in the nutrient solution (0.1/0.0; 0.1/5.0; 0.1/20.0; 1.0/2.5; 1.0/10.0; 1.9/0.0 - control; 1.9/5.0; 1.9/20.0; 2.8/2.5; 2.8/10.0; 3.7/0.0; 3.7/5.0 and 3.7/20.0 mM of S and Ba, respectively). The plants were grown for two growth periods, which consisted of fourteen days of S supply and the eight days of Ba exposure each one. The severe S deficiency decreased the superoxide dismutase activity, regardless of Ba exposure in recently expanded leaves and culms plus sheaths. However, supplemental S supply (above 1.9 mM S, which corresponds to S supply adequate to plant growth) it improved the superoxide dismutase activity in these tissues under high Ba concentrations. Conversely, the severe S deficiency increased the activities of catalase, ascorbate peroxidase, and glutathione reductase in grass leaves slightly, without Ba exposure influence. It was observed that the supplemental S supply also induced the guaiacol peroxidase activity and proline production in culms plus sheaths under high Ba rates, showing values until 2.5 and 3.1 folds higher than the control treatment, respectively. In plants under exposure to 20.0 mM Ba, the supplemental S supply decreased the malondialdehyde content in culms plus sheaths in 17% compared to 1.9 mM S. These results indicate that supplemental S supply can mitigate Ba toxicity in Tanzania guinea grass, mainly by improving superoxide dismutase and guaiacol peroxidase activities, and proline metabolism.

Association between selected alkaline earth elements concentrations in umbilical cord and risk for cleft lip with or without cleft palate

The relationship between alkaline earth elements in utero exposure and the risk of cleft lip with or without cleft palate (CL ± P) remains unclear. We aimed to investigate the associations between the concentration of alkaline earth elements in umbilical cord and risk for CL ± P. A case-control study was carried out in this study, including 78 cases and 142 controls. Association between each metals and the risk of CL ± P were evaluated with conventional logistic regression, bayesian kernel machine regression and weighted quantile sum regression models. Logistic regression model indicated that in utero exposure to higher levels of Barium was associated with increasing risk for CL ± P (odds ratio = 2.79, 95% confidence interval, 1.22-6.38) and for cleft lip with cleft palate (odds ratio = 3.94, 95% confidence interval, 1.45-10.72). Bayesian kernel machine regression model showed the statistical association between the metals mixture and risk difference of CL ± P, and barium was associated with CL ± P risk when all other metals were held fixed at the 25th percentiles (risk difference = 1.07, 95% confidence interval, 1.01-1.14). In weighted quantile sum model, barium accounted for most of the weight index in the combined effect of the metals mixture. The weighted quantile sum index showed that a quartile increase in the index resulted in an increase odds of 1.69 (95% confidence interval, 1.16-2.46) for CL ± P and of 2.11 (95% confidence interval, 1.34-3.35) for CLP. No associations were found in the three statistical models between Calcium, Magnesium and Strontium and the risks of CL ± P. In conclusion, in utero exposure to mixtures of alkaline earth elements was associated with an increased risk for CL ± P, of which barium was likely to be important factors in the development.

Relationship between heavy metal accumulation and histological alterations in voles from alpine and forest habitats of the West Carpathians

The interaction between toxic heavy metals and bio-elements in internal organs and femoral bones and their potential impacts on bone structural properties and renal histopathological changes in bank voles and snow voles were investigated. Our results reveal that heavy metals Hg and Pb accumulate more in femoral bones of alpine habitats than forests. In snow voles, the parameters of the primary osteons' vascular canals (length, average perimeter and area) simultaneously decreased with an increase of Pb and Sr. Wider primary osteons' vascular canals of snow voles contained decreased levels of K, but increased Ba. In bank voles, the number of primary osteons increased in alpine habitats along with K, Hg, and Pb accumulation. In the kidneys of bank voles, rising levels of Rb, Hg, and Zn were detected in alpine habitats. Hg increases the most in kidney tissue from alpine habitats in both vole species, and Hg levels (mean value 0.25 μg/g, max. value 0.55 μg/g) in the renal tissues of bank voles from alpine localities are similar to Hg levels from Hg-polluted industrial areas in other studies. This reflects that alpine areas of the Tatra Mountains are highly contaminated with Hg. The intensity of renal hemosiderosis relates significantly to Zn, Fe, and Cu levels in snow voles, with Fe and Zn levels in bank voles from forest habitats, and with Rb in bank voles from alpine habitats. The intensity of tubule necrosis in renal tissues of bank voles from alpine habitats was negatively related to Se content. In bank voles from forest habitats, significant positive correlations were found between the intensity of glomerular hyperplasia and amounts of Zn. The interactions of the detected element's association with bone tissue and internal organs are discussed.

Barium isotopic fractionation during strong weathering of basalt in a tropical climate

Barium (Ba) is an element which is toxic to humans, plants, and animals. Deciphering the geochemical behavior of Ba in soils is fundamental for assessing the potentials risks posed by Ba. Ba isotopes are a potentially robust tracer of Ba in soils. In this study, the controlling factors of Ba isotopic fractionation in a latosol profile were investigated through sequential-extraction experiments. Furthermore, dissolution experiments were conducted to understand Ba isotopic fractionation during the dissolution of basalts. The sequential-extraction experiments revealed δ^137/134Ba ratios in various fractions that were remarkably heterogeneous: -0.28‰ to -0.15‰ in the exchangeable fraction; -0.32‰ to -0.16‰ in reducible Fe-Mn (oxyhydr)oxides; and 0.06‰ to 0.46‰ in residues. This indicates that light Ba isotopes are preferentially adsorbed on secondary minerals and associated with Fe-Mn (oxyhydr)oxides. Both processes play important roles in storing Ba originally released from minerals. Results of the sequential-extraction and dissolution experiments revealed that light Ba isotopes favored fluids during the dissolution of silicate minerals, while heavy Ba isotopes were prone to being released from interlayers of micaceous layers. Collectively, the dissolution of minerals, adsorption on secondary minerals, and formation of easily reducible Fe-Mn (oxyhydr)oxides govern Ba isotope fractionation and Ba transport in soils.