Search

Extrinsic factors play a significant role during aquaculture feed manufacturing practices. Herein, a 90-day feeding trial was designed in triplicate under controlled environmental conditions to evaluate the efficiency of different chemical forms of dietary cobalt at different dosage levels on growth performance, hematological, and immunological indices of Tor putitora fingerlings. Firstly, cobalt chloride nanoparticles (Co-NPs) and cobalt methionine chelated complex (Co-Met) were synthesized via physical and chemical methods respectively and then characterized for their size, surface morphology, and elemental composition analysis by using X-rays diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Results indicated the crystalline nature of Co-NPs with spherical shape having an average size < 20 nm while Co-Met appeared as an amorphous complex with a honey-comb-like octahedral structure with an average size of 82.69 nm. Afterward, a feeding experiment was executed and fish were divided into three groups, i.e., control group (CG; fed 40% crude protein diet with no mineral added), while the other two groups were fed graded levels (0.5–3 mg/kg; increment of 0.5 mg Co/group) of Co-NPs and Co-Met supplemented diets. Statistical analysis of results by using two-way ANOVA indicated significant (P < 0.001) effect of both chemical forms, dosage levels, and their interaction level on fish indicating a dose-dependent significant effect of different chemical forms of dietary cobalt on fish. Additionally, Co-Met supplemented group of fish at supplementation level of 3 mg/kg diet showed highest growth performance, and improved hemato-immunological as compared to other experimental and control group of fish. [ABSTRACT FROM AUTHOR]

Cobalt (Co) and nickel (Ni) are beneficial and essential elements for plants, respectively, with the latter required for urease activity, which hydrolyzes urea into ammonium in plants. However, excess Co and Ni are toxic to plants and their transport mechanisms in rice are unclear. Here, we analyzed an ethyl methanesulfonate (EMS)-mutagenized rice mutant, 1187_n, with increased Co and Ni contents in its brown rice and shoots. 1187_n has a mutation in OsFPN1, which was correlated with a high Co and Ni phenotype in F2 crosses between the parental line and mutant. In addition, CRISPR/Cas9 mutants exhibited a phenotype similar to that of 1187_n, demonstrating that OsFPN1 is the causal gene of the mutant. In addition to the high Co and Ni in brown rice and shoots, the mutant also exhibited high Co and Ni concentrations in the xylem sap, but low concentrations in the roots, suggesting that OsFPN1 is involved in the root-to-shoot translocation of Co and Ni. The growth of 1187_n and CRISPR/Cas9 lines were suppressed under high Co and Ni condition, indicating OsFPN1 is required for the normal growth under high Co and Ni. An OsFPN1-green fluorescent protein (GFP) fusion protein was localized to the Golgi apparatus. Yeast carrying GFP-OsFPN1 increased sensitivity to high Co contents and decreased Co and Ni accumulation. These results suggest that OsFPN1 can transport Co and Ni and is vital detoxification in rice. [ABSTRACT FROM AUTHOR]

aima I Abdel Hamid,1 Mohamed E Attia,2 Jon M Hirshon,3,4 Mohamed El-Shinawi,5,6 Moustafa El-Hussaini,7 Maged El-Setouhy7,81Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt; 2Orthopedics Departments, Faculty of Medicine, Zagazig University, Zagazig, Egypt; 3Department of Emergency Medicine, University of Maryland, School of Medicine, Baltimore, MD, USA; 4Department of Epidemiology and Public Health, University of Maryland, School of Medicine, Baltimore, MD, USA; 5Department of General Surgery, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 6Galala University, Galala City, Suez, Egypt; 7Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 8Department of Family and Community Medicine, Faculty of Medince, Jazan University, Jazan, Kingdom of Saudi ArabiaCorrespondence: Omaima I Abdel Hamid, Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt, Tel +201001664310, Email [email protected] Introduction: Hip arthroplasty (HA) using implantable metal components is among the commonest orthopedic interventions. However, it can be followed by several complications following corrosion and the release of metal ions. Several studies proved that damaged genomic DNA may contribute to the pathophysiology of mental disorders. Aim: The current work aims to evaluate the psychiatric disorders in metal on polyethylene hip arthroplasty (MOP-HA) patients and its correlation to cobalt/chromium (Co/Cr) levels and genotoxicity. Methods: The work was a longitudinal follow-up study including 34 adults with unilateral primary MOP-HA meeting the inclusion and exclusion criteria. Preoperatively, 6, 12-months-postoperatively, patients were examined for cognitive impairment using mini-mental-state-examination (MMSE), depression using major-depressive-inventory (MDI), and blood samples were collected for estimation of Co/Cr, detection of genotoxicity by single-cell-gel-electrophoresis (comet assay) and serum 8-hydroxy-2'–deoxyguanosine (8-OHdG). Results: Cognitive impairment was reported in 18.5% and 14.8% at 6-months, and 12-months postoperative, respectively. Depressive disorder was recorded in 22.2% at 6-months and 14.8% at 12-months postoperative. The marginal homogeneity tests proved a non-significant difference. There was a non-significant difference in preoperative, 6-months, 12-months postoperative MMSE, and MDI scores. There were significantly increased Co/Cr levels at 6-months postoperative. The levels decreased at 12-months postoperative, however, still significantly higher than preoperative values. There was a significant increase in serum 8-OHdG and the levels were positively correlated to cobalt levels at both 6 and 12-months-postoperative. There was a non-significant difference among preoperative, 6-months, and 12-months postoperative comet assay measurements. Conclusion: From previous findings, we can conclude that will-functioning MOP hip arthroplasty can induce increased ion levels and positively correlated increase in biochemical markers of genotoxicity (8-OHdG). [ABSTRACT FROM AUTHOR]

Excessive cobalt exposure has been shown to induce various adverse health effects in animal and human toxicity studies. However, the relationships between cobalt exposure and obesity, insulin resistance, and metabolic-related disorders are rarely studied in epidemiological studies. This study aimed to explore the dose–response relationships between urinary cobalt concentrations and obesity, insulin resistance, and metabolic-related disorders. Adult participants (≥20 years) from the 2005 to 2018 National Health and Nutrition Examination Survey were included. Restricted cubic splines and the log-binomial regression were adopted. Multivariate adjusted prevalence ratios (95% confidence intervals) comparing extreme quartiles of urinary cobalt concentrations were 1.43 (1.29–1.57) for obesity, 1.43 (1.10–1.86) for insulin resistance, 1.21 (1.09–1.34) for metabolic syndrome, 1.16 (1.10–1.23) for elevated waist circumference, 1.20 (1.09–1.33) for elevated triglycerides, 1.14 (1.01–1.29) for reduced high-density lipoprotein cholesterol (HDL-C), 1.06 (0.98–1.15) for elevated blood pressure, and 0.91 (0.79–1.06) for elevated fasting glucose, respectively. Results from the restricted cubic splines showed that an initial steep increase in risk was followed by a weaker increase in risk or a platform beyond 1.0 µg/L for obesity (prevalence ratio (95% confidence interval): 1.41 (1.29–1.55)), insulin resistance (1.33 (1.07–1.65)), metabolic syndrome (1.18 (1.11–1.31)), elevated waist circumference (1.18 (1.11–1.25)), elevated triglycerides (1.21 (1.11–1.33)), and reduced HDL-C (1.15 (1.01–1.30)), respectively. In conclusion, the prevalence of obesity, insulin resistance, metabolic syndrome, elevated waist circumference, elevated triglycerides, and reduced HDL-C progressively increased with increasing urinary cobalt concentrations. The above associations are non-linear and there is not a "safe threshold" below which there are no toxic effects of cobalt. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to determine the long-term effects of metal-on-metal (MoM) cobalt (Co)-chromium-containing prostheses used in total knee arthroplasty (TKA) on hearing and tinnitus. Methods: A total of 88 patients with the normal otoscopic examination and normal blood B12 levels, consisting of 44 patients who had been using MoM Co-chromium-containing total knee prosthesis for more than 5 years, and 44 non-implanted patients with similar demographic characteristics, were randomly selected and included in the study. Patients with previous ear surgery, chronic middle ear disease, or conductive hearing loss were excluded from the study. All participants were evaluated with puretone audiometry (PTA), distortion product otoacoustic emission (DPOAE), tinnitus handicap inventory (THI), and tinnitus reaction questionnaire (TRQ). Results: The mean age of the 88 patients was 67.22±10.4 years. The mean age of 44 patients who underwent TKA at least 5 years ago was 72.89±7.18 years, 75% of these patients had bilateral prostheses, and the mean prosthesis duration was 11.00±5.08 years (range 5-25). The two groups were compared statistically using PTA, DPOAE, THI, and TRQ scores. When the patient groups with and without prostheses were compared in terms of hearing and tinnitus, we did not find a significant difference between the two groups (p>0.05). Conclusion: In our study, we observed that the long-term use of MoM Co-chromium total knee prostheses did not have an ototoxic effect, contrary to what was believed. We also found that prolonged prosthesis duration or undergoing bilateral surgery did not worsen hearing and tinnitus. [ABSTRACT FROM AUTHOR]

The treatment of metal-polluted wastes is a challenging issue of environmental concern. Metals can be removed using microbial biomass, and this is an interesting approach towards the design of eco-friendly technologies for liquid waste treatment. The study reported here aimed to optimize nickel and cobalt biosorption from aqueous solutions using three native metal–resistant Serratia marcescens strains. Ni(II) and Co(II) biosorption by S. marcescens strains was found to fit better to Langmuir's model, with maximum uptake capacities of 13.5 mg g−1 for Ni(II) ions and 19.9 mg g−1 for Co(II) ions. Different experimental conditions of initial metal concentration, pH, initial biomass, and temperature were optimized using the Plackett–Burman method, and, finally, biomass and metal concentration were studied using the response surface methodology (RSM) to improve biosorption. The optimum uptake capacities for Co(II) ions by the three biosorbents used were obtained for initial metal concentrations of 35–40 mg L−1 and an initial biomass of 6 mg. For Ni(II) ions, the optimum uptake capacity was achieved with 1 mg of initial biomass for S. marcescens C-1 and C-19, and with 7 mg for S. marcescens C-16, with initial concentrations of 20–50 mg L−1. The results obtained demonstrate the viability of native S. marcescens strains as biosorbents for Ni(II) and Co(II) removal. This study also contributes to our understanding of the potential uses of serpentine microbial populations for the design of environmental cleanup technologies. [ABSTRACT FROM AUTHOR]

Purpose: To report the clinical case of a 65-year-old male who developed retinal dysfunction following cobalt-chromium toxicity. Methods: A review of the clinical, haematological, radiological and electrophysiological investigations into a single patient was performed in order to form a case report. Results: A 65-year-old male presented to his ophthalmologist with a 1-year history of worsening vision on the background of a multisystem illness including motor axonopathy, pericardiomyopathy and bulbar palsy. His medical history included hypertension, hypercholesterolaemia and a metallic hip prosthesis. Ocular examination revealed significantly reduced visual acuity bilaterally along with very poor colour vision. Cornea, fundi and optic discs all appeared normal. Bilateral moderate nuclear sclerosis was noted. Basic investigations including mitochondrial studies, auto-immune screen and MRI of brain were unremarkable. Further investigations showed significantly elevated plasma cobalt and chromium levels. Electrophysiological studies revealed an abnormality in all phases of the ERG including a negative b-waveform, suggestive of inner retinal pathology. Following subsequent revision of the hip, cobalt and chromium levels decreased and the patient's vision improved. Further electrophysiological testing indicates a persistent ERG abnormality despite a significant improvement in both the patient's visual acuity and colour vision. Conclusions: These results suggest that cobalt-chromium toxicity can cause inner retinal dysfunction. [ABSTRACT FROM AUTHOR]

An experiment was conducted with young, male, crossbred chicks to investigate the interaction between dietary cobalt, methionine and experimental Eimeria acervulina infection (duodenal coccidiosis). Coccidiosis and dietary cobalt (250 mg/kg) depressed weight gain and efficiency of feed utilization; cobalt toxicity, however, was exacerbated by the coccidial infection, resulting in a depression in performance greater than could be accounted for by the independent additive effect of each entity. Dietary cobalt increased the cobalt concentration of the liver, kidney and gallbladder (with bile); experimental coccidiosis in the absence of excess dietary methionine resulted in a twofold increase in cobalt deposition in the liver and gallbladder. Excess supplemental methionine partially alleviated the decrease in chick performance and the increase in tissue cobalt content caused by dietary cobalt in both healthy and infected chicks, but with a slightly greater efficacy in the coccidiosis-infected chicks.

Cobalt, above 1 microM concentration was growth inhibitory for both A. doliolum and A. nidulans. Its toxicity was mitigated by sulphur containing amino acids (cystine and cysteine), however, methionine could not mitigate the cobalt toxicity at all.

The effect of EDTA on acute cobalt toxicity in rats was the subject of our investigation. There was complete effectiveness for two methods of treatment of the Co and EDTA, except when the CoCl2 was given orally and EDTA intraperitoneally. When the CoCl2-EDTA complex was given orally or intraperitoneally there were no deaths, not even at LD100 values of the CoCl2. No noteworthy changes were brought about in the hematological parameters and serum parameters of the animals receiving the CoCl2-EDTA complexes after a week's treatment. Significant differences appeared in the variation of some blood parameters measured 12 hours after the administration of the Co/CH3-COO)2-EDTA complex compared with the same parameters measured on giving only Co(CH3-COO)2.

The concentrations of cobalt and chromium have been measured in the urine of 22 patients who had received uncemented hip prostheses made from cobalt, chromium and molybdenum alloy, and in 21 patients who had not received prostheses, using absorption spectrophotometry. The results were statistically analysed using the Wilcoxon test. The levels of cobalt in the urine in the patients with uncemented prostheses did not show a significant increase, indicating that there is no greater risk of cobalt toxicity. The concentration of chromium was significantly raised (p less than 10(-2) in the urine of patients with uncemented prostheses, and in three of these patients significant corrosion had occurred.

All chambers of the heart are affected in experimental cobalt cardiomyopathy, with atrial predilection. The primary morphological alteration is mitochondrial damage that possibly reflects an enzymatic block of oxidative decarboxylation at pyruvate and ketogluterate levels. In acute cobalt toxicity chelation of calcium may also be a contributory factor, resulting in deficient utilization of high-energy phosphates. Experimental cobalt cardiomyopathy requires preconditioning factors: protein deficiency appears to be one of them. Vegetative polypoid endocarditis is an important accompaniment in the model used, suggesting that in rats on a protein deficient diet cobalt produced endothelial damage in addition to a cardiocyte injury.

This paper presents the results of a study of the physical properties of a hydrophobic deep eutectic solvent (HDES) based on Aliquat 336 and thymol. A solid–liquid phase diagram was built based on the glass temperatures of the Aliquat 336/thymol mixture in different molar ratios. For the first time, the temperature dependences of the density, viscosity, and refractive index of the suggested HDES have been studied. A study of the extraction of Co(II) and Ni(II) ions was carried out under various conditions with HDES Aliquat 336/thymol as an extractant: the influence of the concentration of hydrochloric acid, the concentration of ammonium/lithium/sodium chloride, and the volumetric ratio of phases was studied. The mechanism of the extraction of Co(II) ions by the proposed HDES has been established. Based on the obtained experimental data, it was shown that a Co/Ni pair can be separated from hydrochloric acid solutions with the proposed HDES. [ABSTRACT FROM AUTHOR]

Micronutrients play key roles in numerous metabolic processes in cyanobacteria. However, our understanding of whether the micronutrient cobalt influences the productivity of freshwater systems or the occurrence of cyanobacterial blooms is limited. This study aimed to quantify the concentration of Co necessary for optimal cyanobacterial growth by exposing Microcystis aeruginosa to a range of Co concentrations under culture conditions. Extended exposure to concentrations below ˜0.06 μg · L−1 resulted in notable inhibition of M. aeruginosa growth. A clear negative relationship was observed between Co concentration in solution and intracellular Fe quota of M. aeruginosa, possibly due to decreased transport of Fe at higher Co concentrations. Cyanocobalamin and any Co within the structure of cyanocobalamin appears to be non‐bioavailable to M. aeruginosa, instead they likely rely on the synthesis of a structural variant – pseudocobalamin, which may have implications for the wider algal community as the variants of cobalamin are not necessarily functionally exchangeable. To evaluate the likelihood of Co limitation of cyanobacterial growth under field conditions, a survey of 10 freshwater reservoirs in South‐Eastern Australia was conducted. Four of the ten sites had dissolved Co concentrations below the 0.06 μg · L−1 threshold value. All four of these sites rarely undergo cyanobacterial blooms, strengthening evidence of the potential for Co to limit growth, perhaps either alone or in combination with phosphorus. [ABSTRACT FROM AUTHOR]

In light of potential negative health effects of cobalt exposure, a characterization of inflammatory mechanisms in exposed individuals is warranted. The current study investigated cobalt exposure in the Swedish hard metal industry and its relationship to inflammatory markers, including NLRP3 inflammasome activation and white blood cell (WBC) counts. Inhalable cobalt and dust exposures, and systemic cobalt levels, were determined for 72 workers in the hard metal industry and linear regression models were applied to correlate exposure to markers of inflammasome activation and WBC counts. Mean exposures to inhalable dust (0.11 mg/m3) and cobalt (0.0034 mg/m3) were below the Swedish occupational exposure limits, and these low exposures did not correlate with any investigated outcomes. Instead, cobalt blood levels significantly correlated with a ca 10% decrease in IL-18 plasma levels per 10 nM cobalt increase. Furthermore, pre-shift cobalt blood and/or urine levels significantly correlated with some WBC measures, including decreased neutrophil-to-lymphocyte ratio, increased lymphocyte-to-monocyte ratio, and lymphocyte counts. The low inhalable particle exposures had no impact on WBC counts and inflammasome activation. Instead, systemic cobalt levels, which also include skin exposure, demonstrated possible suppressive effects on inflammatory responses in cobalt-exposed individuals in the hard metal industry. [ABSTRACT FROM AUTHOR]

By decreasing root 1-aminocyclopropane-1-carboxylate (ACC) content and plant ethylene production, the microbial enzyme ACC deaminase is a widespread beneficial trait of plant growth-promoting rhizobacteria (PGPR), ameliorating ethylene-mediated root growth inhibition. However, relatively little is known about whether bacterial ACC deaminase modulates root architecture and root hair traits. Thus the dwarf tomato (Solanum lycopersicum) cultivar Micro-Tom was inoculated in vitro with Pseudomonas brassicacearum Am3, its ACC deaminase deficient mutant T8-1, a known PGPR strain Variovorax paradoxus 5C-2 or chemically treated with agents that promoted or inhibited ethylene production or sensitivity (Ag+, Co2+, and ACC). ACC treatment reduced both root elongation and the number of lateral roots, while ethylene inhibitors (Ag+, Co2+) and V. paradoxus 5C-2 promoted primary root elongation, but differentially affected lateral root length and number. Ag+ stimulated lateral root development, while Co2+ and V. paradoxus 5C-2 did not. Inoculation with P. brassicacearum Am3 and T8-1 inhibited elongation of the primary and lateral roots at a high inoculum concentration (106 cells cm3). All bacterial strains significantly increased the length and number of root hairs, with these effects more pronounced in P. brassicacearum Am3 than in the mutant T8-1. Treatment with Ag+ inhibited root hair formation and elongation, while Co2+ had the opposite effects. ACC treatment had no effect on root hair elongation but increased root hair density. While root growth inhibition caused by P. brassicacearum Am3 was independent of ACC deaminase, the promotion of root hair elongation and density by this strain was augmented by ACC deaminase activity. Thus ACC deaminase can modulate the morphological impacts of bacteria on root hair response by affecting plant ethylene content. [ABSTRACT FROM AUTHOR]

Background and purpose -- We have previously reported that the whole blood (WB) chromium (Cr) and cobalt (Co) ion levels decrease in the short term after ReCap-M2a-Magnum large-diameter head (LDH) metal-on-metal (MoM) total hip arthroplasty (THA). This study reports long-term metal ion levels and clinical outcomes after ReCap-Magnum THA. Patients and methods -- ReCap-M2a-Magnum LDH THA was used in 1,450 patients in our hospital district from 2005 to 2012. Median follow-up time was 10 years. 991 patients had 2 or more metal ion measurements. The median measurement interval was 4 years. Individual metal ion change was assessed using logarithmic metal ion values in a random coefficient model. Kaplan--Meier survival estimates were calculated for revision surgery for any reason for revision, and separately for metal-related adverse events (metal ions above safe upper limit [SUL], revision due to ARMD, or pseudotumor). Results -- Geometric mean of Cr decreased from 1.8 ppb (geometric standard deviation [GSD] 1.8) to 1.0 ppb (GSD 2.8, p < 0.001). The Co levels decreased from 1.7 ppb (GSD 2.4) to 1.4 ppb (GSD 2.8, p < 0.001). The hip-specific survival was 85% for revision due to any reason at 14 years and the hip-specific survival for any metal-related adverse event was 69% at 14 years. Interpretation -- WB Cr and Co levels continued to decrease in the long-term follow-up of ReCap-M2a-Magnum THA patients. The amount of metal-related adverse events was rather high, but revision surgery was seldom required. We suggest that after 10 years from the implantation a 5-year measurement interval may be sufficient for asymptomatic ReCap-M2a-Magnum patients. [ABSTRACT FROM AUTHOR]

A dispersive liquid-liquid microextraction procedure (DLLME) was developed and validated for the determination of cobalt and copper in environmental samples by flame atomic absorption spectrometry. The optimisation parameters of DLLME procedure including amount of chelating reagent (0.05 mg dithizone), pH (6), extraction type and volume (250 µL chloroform) and dispersive solvent (1000 µL acetone), matrix effect was investigated. Several validation variables, such as limit of detection and quantification, linearity, recovery, precision and trueness were also tested. The quantification limits of Co and Cu were found to be 9.01 and 6.14 µg L−1, respectively. The enrichment factor was 20. The trueness of the method was tested by analysis of certificated reference material (BCR-715) for Cu and calculated less than −1.11% with the relative error. The presented green microextraction method was profitably applied to real samples and the spiked recoveries calculated were more than 95% with the relative standard deviation less than 8.4%. [ABSTRACT FROM AUTHOR]

Cobalt is a transition metal located in the fourth row of the periodic table and is a neighbor of iron and nickel. It has been considered an essential element for prokaryotes, human beings, and other mammals, but its essentiality for plants remains obscure. In this article, we proposed that cobalt (Co) is a potentially essential micronutrient of plants. Co is essential for the growth of many lower plants, such as marine algal species including diatoms, chrysophytes, and dinoflagellates, as well as for higher plants in the family Fabaceae or Leguminosae. The essentiality to leguminous plants is attributed to its role in nitrogen (N) fixation by symbiotic microbes, primarily rhizobia. Co is an integral component of cobalamin or vitamin B12, which is required by several enzymes involved in N2 fixation. In addition to symbiosis, a group of N2 fixing bacteria known as diazotrophs is able to situate in plant tissue as endophytes or closely associated with roots of plants including economically important crops, such as barley, corn, rice, sugarcane, and wheat. Their action in N2 fixation provides crops with the macronutrient of N. Co is a component of several enzymes and proteins, participating in plant metabolism. Plants may exhibit Co deficiency if there is a severe limitation in Co supply. Conversely, Co is toxic to plants at higher concentrations. High levels of Co result in pale-colored leaves, discolored veins, and the loss of leaves and can also cause iron deficiency in plants. It is anticipated that with the advance of omics, Co as a constitute of enzymes and proteins and its specific role in plant metabolism will be exclusively revealed. The confirmation of Co as an essential micronutrient will enrich our understanding of plant mineral nutrition and improve our practice in crop production. [ABSTRACT FROM AUTHOR]

Introduction. Chromium and cobalt are essential trace elements that are required only in a small amount, otherwise their excess can cause toxic effects. Aim. The aim of this study was to determine the effects of chromium (III) and cobalt (II) and their combinations on genotoxicity in human fibroblasts cells (BJ). Material and methods. In this work, comet and micronucleus assays were used. The BJ cells were exposed to chromium chloride and cobalt chloride at concentration ranges from 100 to 1400 µM. Mixtures of these elements were prepared so as to examine interactions between them. Results. The present study shows the genotoxic effects of chromium (III) and cobalt (II) and their mixtures on BJ cells. In the comet assay, no comets were observed at the lowest concentrations; in the higher, a significant increase in their percentage was observed. In the other assay (formation of micronuclei), a statistically significant increase in the number of cells with micronuclei was observed in the BJ cells spiked with cobalt chloride and chromium chloride. In the case of simultaneous incubation of chromium chloride at 200 µM and cobalt chloride at 1000 µM in the BJ line, antagonism was observed. However, the interaction of chromium chloride at the 1000 µM and cobalt chloride at 200 µM leads to synergism between the studied elements. Conclusions. Cobalt (II) and chromium (III) show genotoxic properties, they induce breaks in double and single-stranded DNA and they cause formation of AP-sites that do not have purine or pyrimidine bases. [ABSTRACT FROM AUTHOR]

Cobalt exposure has adverse health effects on the cardiovascular system in occupational and laboratory studies, but these effects have not been assessed in the general population. We aimed to determine whether serum cobalt levels had relationship with the prevalence of cardiovascular disease (CVD) in the general population. Using data from the National Health and Nutrition Examination Survey (NHANES) (2015–2016), we performed the cross-sectional study. We analyzed the baseline characteristics of 3389 participants (1623 men and 1766 women). Generalized linear models and restricted cubic spline plots curve were undertaken to elucidate the relationship. Stratified subgroup analysis was tested to exclude interaction between different variates and cobalt. Our results showed that the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for CVD prevalence across the quartiles of cobalt were 0.94 (0.67, 1.30), 1.55 (1.15, 2.10), and 1.74 (1.28, 2.35) compared with lowest quartile. The restricted cubic spline curve also suggested nonlinear and positive association between cobalt and CVD (P for nonlinearity = 0.007). In summary, our cross-sectional results verify that higher cobalt levels are associated with a higher prevalence of cardiovascular disease. [ABSTRACT FROM AUTHOR]

Calixarenes, which have a great place in supramolecular chemistry, have become the most prominent macrocyclic compounds in synthetic organic chemistry due to their easy synthesis and functionalization. In this study, p-tert-butyl calix[4]arene dihydrazide derivative was synthesized and then reacted with 3-oxo-3,4-dihydro-2 H-benzo[b][1,4] thiazin-2-ylideneacetyl chloride to prepare new calixarene based chromophore compound 4. The structure of the synthesized compound was elucidated by spectroscopic methods such as 1H NMR 13C NMR and FT-IR spectroscopy. Chromogenic and fluorescence properties of compound 4 were evaluated. It was observed from both studies that compound 4 was Co2+ selective and shows fluorescence Switched-off behavior. Stoichiometry, binding constant and the detection limit were calculated. The stoichiometry between compound 4 and Co2+ was found to be 1:1. The binding constant value (K) was calculated as 666.67 M− 1 using Benesi–Hildebrand equation, while the detection limit for Co2+ ion was calculated as 0.0465 µM. [ABSTRACT FROM AUTHOR]

Background: Sensitization requires exposure to an allergen with subsequent production of a "danger "signal. In the skin, keratinocytes are the main producers of these signals. Objective: To compare dose- and time-effects of cobalt on the viability of and cytokine release from HaCaT cells cultured at low or high calcium. Method: To model two separate states of differentiation of keratinocytes, HaCaT cells were cultured under low or high calcium conditions. HaCaT were exposed to different concentrations of cobalt chloride (10 μm to 5 mM) over time (30 minutes– 48 hours). Cell viability was measured with the Cell-Titer Blue Viability assay. Cytokine production was measured using a bead-based immunoassay and flow cytometry. Gene expression was quantified using qPCR. Data was analyzed by ANOVA and linear mixed model. Results: Viability of the cells was dose- and time-dependent. A linear mixed statistical model showed that cobalt exposure induces increase in IL-6, CXCL8 and CCL2 production over time and whereas increase of IL-6 and a decrease of CCL2 was associated with increasing cobalt chloride concentrations. When comparing the cells incubated under high and low calcium conditions, the more differentiated cells in the high concentration were found to exert a stronger response in terms of IL-6 release. Conclusions: Our data suggest that cobalt chloride triggered an alarm system in HaCaT cells, and proinflammatory cytokines/chemokines were secreted in a dose- and time-dependent manner. When high and low calcium incubations were compared, the difference was seen only for IL-6. These findings indicate that the effect of cobalt chloride on cell toxicity occurs throughout the living epidermis. [ABSTRACT FROM AUTHOR]

Chromium (III) and cobalt (II) are necessary elements required for the proper functioning of the organism, but their excess can cause toxic effects. They are the basic components of implants and are also commonly used in medicine as components of dietary supplements, vitamin and mineral products and energy drinks. The aim of this study was to investigate the effect of cobalt (II) and chromium (III) and their combination on BJ cells. In the study, BJ cells were exposed to CoCl2 or CrCl3 at concentrations ranging from 100 to 1400 µM, and the cytotoxicity of chromium (III) and cobalt (II) and their mixtures was assessed by MTT reduction, LDH release and NRU assays. The outcome of this work reveals the cytotoxic effects of chromium (III) and cobalt (II) and their mixtures on BJ cells. In the cytotoxicity assays, at low concentrations of CoCl2 and CrCl3, stimulation of cell proliferation was observed. In higher concentrations, the cell viability decreased for the tested line in all the assays. During the simultaneous incubation of fibroblasts with 200 µM of CrCl3 and 1000 µM of CoCl2, antagonism was observed: chromium (III) at the concentration of 200 µM induced protection from cobalt (II) toxicity; in the case of interaction of chromium chloride at 1000 µm and cobalt chloride at 200 µM, the protective effect of CrCl3 on CoCl2 was not observed. In the latter case, synergism between these elements was noted. Our work indicates that cobalt (II) and chromium (III) show cytotoxic properties. These metals have a destructive effect on the cell membrane, lysosomes and mitochondria, which leads to disorders of cell metabolism. [ABSTRACT FROM AUTHOR]

Cobalt is an essential microelement which is an indispensable part of several enzymes and co-enzymes. Cobalt ions may occur in the environment from both natural sources and due to human activities. This metal is very widespread in the natural environment and can be formed due to anthropogenic activity. Toxic effects produced by cobalt and its compounds depend on the physical and chemical properties of these complexes, including their electronic structure, ion parameters (charge-size relations) and kinetics. Cobalt has both beneficial and harmful effects on human health. Cobalt is beneficial for humans because it is a part of vitamin B12, which is essential to maintain human health. If humans and animals are exposed to levels of cobalt normally found in the environment, it is not harmful. When excessive cobalt amounts enter a human body, multiple and chronic harmful health effects can occur and the longer the cobalt ions are stored in the body, the more changes they cause in cells. Cobalt gets into a body via several ways: mainly with food, via the respiratory system, through the skin or as a component of various biomaterials. Despite this metal being abundant, much of our knowledge on cobalt toxicity is based mainly on studies performed on animals. Undoubtedly, inorganic forms of cobalt are toxic as they accumulate in various tissues and can evoke a chain of pathological cascade changes in cells. Although some cobalt effects might be beneficial for medicine. Therefore, the purpose of our review is to provide the current analysis about the most significant regulatory, pathophysiological and epigenetic effects of Co2+ in a human body

A facile and sensitive spectroscopic detection method for the detection of cobalt ion was introduced by the use of the surface plasmon resonance of silver nanotriangles (AgTrngs). After successful capping and functionalizing of AgTrngs, with an average edge length of ~ 54 nm, by trisodium citrate (TSC) and L-Cysteine, they were employed for the detection of cobalt ion based on the change in their in-plane dipole resonance. According to the obtained results, the developed sensor showed a response time as short as 10 s with a detection limit of 3.5 nM in the concentration range of 10–100 nM; in addition, this sensor needs a small volume of samples for cobalt ion determination that makes it ideal for the analysis of the body fluids as well as other aqueous effluents. Finally, based on the transmission electron microscopy, the oxidation of AgTrngs by cobalt ion was proposed as the detection mechanisms that result in the decrease in the in-plane dipole plasmon resonance of AgTrngs. [ABSTRACT FROM AUTHOR]

Although a powdered form of hydroxyapatite (p-HdA) has been studied for the adsorption of heavy metals that contaminate the restoration sites of decommissioned nuclear power plants, most of the studies are limited in the laboratory due to the head loss and post-separation in practical applications. Herein, we fabricated a porous bead form of HdA (b-HdA) as a novel adsorbent for removing radionuclides from aqueous environments via a facile synthesis by mixing the p-HdA precursor and polyvinyl butyral (PVB) as a binder and added a sintering process for the final production of a porous structure. The spherical b-HdA with an approximate diameter of 2.0 mm was successfully fabricated. The effectiveness of the b-HdA at removing Co(II) was investigated via the adsorption equilibrium at various experimental temperatures. The b-HdA exhibited the adsorption capacity for Co(II) ions with a maximum of 7.73 and 11.35 mg/g at 293 K and 313 K, respectively. The experimental kinetic data were well described using a pseudo-second-order kinetic model, and the adsorption mechanisms of Co(II) onto the b-HdA were revealed to be a chemisorption process with intraparticle diffusion being the rate-limiting step. In addition, the competitive adsorption onto the b-HdA with the order of U(VI) > Co(II) > Ni(II) > Sr(II) > Cs(I) was also observed in the multi-radionuclides system. Considering the advantages of the size, applicability to the continuous-flow column, and the easy separation from treated water, the b-HdA can be an excellent absorbent with high potential for practical applications for removing radionuclides. [ABSTRACT FROM AUTHOR]

Construction and demolition activities generate approximately two thirds of the world’s waste, with concrete-based demolition material accounting for the largest proportion. Primary aggregates are recovered and reused, although the cement-rich fine fraction is underutilised. In this study, single metal batch sorption experiments confirmed that crushed concrete fines (CCF) are an effective sorbent for the maximum exclusion of 45.2 mg g−1 Cd2+, 38.4 mg g−1 Co2+ and 56.0 mg g−1 MoO4 2− ions from aqueous media. The principal mechanisms of sorption were determined, by scanning electron microscopy of the metal-laden CCF, to be co-precipitation with Ca2+ ions released from the cement to form solubility limiting phases. The removal of Co2+ and MoO4 2− ions followed a zero-order reaction and that of Cd2+ was best described by a pseudo-second-order model. The Langmuir model provided the most appropriate description of the steady state immobilisation of Cd2+ and Co2+, whereas the removal of MoO4 2− conformed to the Freundlich isotherm. Long equilibration times (>120 h), loose floc formation and high pH are likely to limit the use of CCF in many conventional wastewater treatment applications; although, these properties could be usefully exploited in reactive barriers for the management of contaminated soils, sediments and groundwater. [ABSTRACT FROM AUTHOR]

This study aimed to systematically investigate the ototoxic potential of cobalt in patients with a metal-on-metal (MoM) hip implant, using objective auditory and vestibular assessments and a questionnaire. The results of the objective evaluation were published previously, whereas the current study focused on the questionnaire outcome and its relationship to the blood cobalt level. Design and study sample: Twenty patients (33–65 years) with a primary MoM hip implant and 20 non-implanted control subjects, matched for age, gender, and noise exposure, received a questionnaire to evaluate the presence of several hearing and balance symptoms (part 1) and general neurological issues (part 2). Concerning part 1, the proportion of auditory-related symptoms in general (p = 0.022) and tinnitus (p = 0.047) was significantly higher in the MoM patient group, whereas no group difference was found for hyperacusis, increased listening effort, and decreased speech understanding. Concerning part 2, no significant group differences were detected. Within the MoM patient group, the questionnaire outcome was not significantly different between the low-exposure and high-exposure subgroups according to the blood Co level. In line with our previous study, these results potentially imply Co-induced impairment to the auditory system, despite the lack of a clear dose–response relationship. [ABSTRACT FROM AUTHOR]

Excessive doses of toxic metals such as cobalt may cause detrimental hazards to exposed organisms. Six groups of onion bulbs were formed to investigate the therapeutic effects of grape seed extract (GSE) against cobalt(II) nitrate (Co(NO3)2) exposure in Allium cepa L. root tips. Control group was irrigated with tap water, while the latter groups were exposed to 150 mg/L GSE, 300 mg/L GSE, 5.5 ppm Co(NO3)2, 5.5 ppm Co(NO3)2 + 150 mg/L GSE and 5.5 ppm Co(NO3)2 + 300 mg/L GSE, respectively. Co(NO3)2 treatment seriously inhibited the root growth, germination and weight gain of the bulbs. Mitotic index was significantly decreased, whereas the chromosomal aberrations and micronuclei incidence exhibited a remarkable increase. In addition, Co(NO3)2 induced a variety of anatomical disorders in onion roots. Lipid peroxidation levels of the cellular membranes were assessed measuring the malondialdehyde content (MDA). MDA amount in Co(NO3)2-treated group reached the highest level among all groups. Co(NO3)2 treatment enhanced the activity of superoxide dismutase and catalase. The addition of GSE to Co(NO3)2 solution substantially suppressed the negative effects of Co(NO3)2 in a dose-dependent manner by strengthening the antioxidant defence system and reducing the cytotoxicity. Moreover, there was a significant recovery in growth parameters following the grape seed addition to Co(NO3)2. GSE had a remarkable reduction in genotoxicity when treated as a mixture with Co(NO3)2. Overall data obtained from this investigation proved that GSE, as a promising functional by-product, had a protective effect on Allium cepa L. against the toxic effects of Co(NO3)2. [ABSTRACT FROM AUTHOR]

Background and purpose — The accelerated wear of poorly functioning metal-on-metal (MoM) hip implants may cause elevated whole-blood cobalt (Co) and chromium (Cr) levels. Hematological and endocrinological changes have been described as the most sensitive adverse effects due to Co exposure. We studied whether there is an association between whole-blood Co/Cr levels and leukocyte, hemoglobin, or platelet levels. Patients and methods — We analyzed whole-blood Co and Cr values and complete blood counts (including leukocytes, hemoglobin, platelets) from 1,900 patients with MoM hips. The mean age at the time of whole-blood metal ion measurements was 67 years (SD 10). The mean time from primary surgery to whole-blood metal ion measurement was 8.2 years (SD 3.0). The mean interval between postoperative blood counts and metal ion measurements was 0.2 months (SD 2.7). Results — The median Co value was 1.9 µg/L (0.2–225), Cr 1.6 µg/L (0.2–125), mean leukocyte count 6.7 × 109/L (SD 1.9), hemoglobin value 143 g/L (SD 13), and platelet count 277 × 109/L (SD 70). We did not observe clinically significant correlations between whole-blood Co/Cr and leukocyte, hemoglobin, or platelet counts. Interpretation — Elevated whole-blood Co and Cr values are unlikely to explain abnormal blood counts in patients with MoM hips and the reason for possible abnormal blood counts should be sought elsewhere. [ABSTRACT FROM AUTHOR]

Recently, catastrophic failure (i.e., dissociation between the metal femoral head and stem due to stem neck deformation) after total hip arthroplasty (THA) has been reported. Early detection of this complication is very important, because it is accompanied by an increased cobalt concentration in the body, which might influence systemic conditions such as heart failure and immune system diseases. However, early detection of stem neck deformation is considered as difficult. In most cases in the literatures, the diagnosis was made at the time of acute dissociation. We report a case of early detection of stem neck deformation with the 'Bowing-head sign' before acute dissociation. The patient is a 71-year old woman complained of a clicking sensation in the right hip during regular follow-up after THA with a 32-mm cobalt/chromium head with polyethylene insert for osteoarthritis performed 7 years previously. The plain radiograph showed that the angle between the metal femoral head and the axis of the stem neck was not perpendicular ('Bowing-head sign'). Dynamic evaluation under fluoroscopy showed movement of the stem neck in the metal femoral head with hip abduction and adduction. Laboratory data showed abnormal serum cobalt (6.3 μg/L, normal < 1 μg/L) and chromium (3.8 μg/L, normal < 5 μg/L) levels. Considering those radiographic findings, deformation of the stem neck due to trunnionosis was diagnosed, and elective revision surgery was performed without any complications. Plain radiographs after THA should be assessed with attention to this complication, 'Bowing-head sign' must not be overlooked. [ABSTRACT FROM AUTHOR]

Developing brain is very sensitive to the influence of environmental factors during gestation and the neonatal period. The aim of the study is to assess cobalt and iron accumulation in the brain as well as changes in the expression of iron-regulatory proteins transferrin receptor 1, hepcidin, and ferroportin in suckling mice. Perinatal exposure to cobalt chloride increased significantly cobalt content in brain tissue homogenates of 18-day-old (d18) and 25-day-old (d25) mice inducing alterations in brain iron homeostasis. Higher degree of transferrin receptor 1 expression was demonstrated in cobalt chloride-exposed mice with no substantial changes between d18 and d25 mice. A weak ferroportin expression was found in 18-day-old control and cobalt-treated mouse brain. Cobalt exposure of d25 mice resulted in increased ferroportin expression in brain compared to the untreated age-matched control group. Hepcidin level in cobalt-exposed groups was decreased in d18 mice and slightly increased in d25 mice. The obtained data contribute for the better understanding of metal toxicity impact on iron homeostasis in the developing brain with further possible implications in neurodegeneration. • Late prenatal and early postnatal exposure to cobalt chloride increases significantly brain Co content in suckling mice. • CoCl 2 provokes changes in the expression of iron-regulatory proteins transferrin receptor 1, hepcidin and ferroportin. • Cobalt toxicity affects iron homeostasis in the developing brain with further possible implications in neurodegeneration. [ABSTRACT FROM AUTHOR]

Nickel and cobalt are essential elements that become toxic at high concentrations. Little is known about nickel and cobalt toxicity in aquatic animals. This study aimed to investigate acute and chronic toxicity of nickel and cobalt in Japanese flounder (Paralichthys olivaceous), with emphasis on oxidative stress reactions, histopathological changes, and differences in gene expression. The lethal concentration for 50% mortality (LC 50) in 3 and 8 cm Japanese flounder exposed to nickel for 96 h was found to be 86.2 ± 0.018 and 151.3 ± 0.039 mg/L; for cobalt exposure, LC 50 was 47.5 ± 0.015 and 180.4 ± 0.034 mg/L, respectively. Chronic nickel and cobalt exposure caused different degrees of oxidative enzyme activity changes in gill, liver, and muscle tissues. Erythrocyte deformations were detected after acute or chronic exposure to nickel and cobalt. the nickel and cobalt exposure also caused pathological changes such as spherical swelling over other gill patches, rod-like proliferations in the gill patch epithelial cell layer, and disorder in hepatocyte arrangement, cell swelling, and cytoplasm loosening. RNA-Seq indicated that there were 184 upregulated and 185 downregulated genes in the liver of Japanese flounder exposed to 15 mg/L nickel for 28 d. For cobalt, 920 upregulated and 457 downregulated genes were detected. Among these differentially expressed genes, 162 were shared by both nickel and cobalt exposure. In both nickel and cobalt, pathways including fatty acid elongation, steroid biosynthesis, unsaturated fatty acid biosynthesis, fatty acid metabolism, PPAR signaling, and ferroptosis were significantly enriched. Taken together, these results aided our understanding of the toxicity of nickel and cobalt in aquatic animals. Image 1 • Heterozygous clonal Japanese flounder with genetic similarity of 1.00 were used. • Lethal concentration for 50% mortality that exposed to nickel and cobalt were determined in Japanese flounder. • Chronic nickel and cobalt exposure changed oxidative enzyme activity in Japanese flounder. • Nickel and cobalt induced stress response signaling pathways were explored in Japanese flounder. Chronic nickel and cobalt exposure induced ferroptosis in the liver of Japanese flounder. [ABSTRACT FROM AUTHOR]

Aims: Knowledge on the ecophysiology of cobalt hyperaccumulator species is limited. The nickel hyperaccumulator Rinorea cf. bengalensis from Borneo can accumulate high concentrations of cobalt in nature. This study investigates the cobalt accumulation potential of Rinorea cf. bengalensis in relation to nickel concentrations in soils and the subsequent tissue and cellular-level distributions of cobalt, nickel and major cations. Methods: Seedlings of Rinorea cf. bengalensis were grown in mixed treatments on ultramafic soil containing a high concentration of available nickel. Cobalt and nickel salts were then added to the soil to study their interactions. The tissue and cellular-level distributions of cobalt, calcium, nickel, and potassium were investigated using synchrotron-based X-ray fluorescence microscopy. Results: The maximum foliar cobalt concentration reached 1200 μg g−1. Accumulation of cobalt competed with nickel accumulation although nickel seems to stimulate cobalt phloem translocation. Plants suffered toxicity in the treatment with the highest soil cobalt concentration. Cobalt and nickel have contrasting distribution patterns in the leaves of Rinorea cf. bengalensis, with cobalt mainly excreted on the surface of the leaves, whereas nickel is localised in foliar epidermal cells. Conclusions: Rinorea cf. bengalensis can accumulate high concentrations of cobalt, but is intrinsically more tolerant to nickel. It does not rely on a similar sequestration mechanism for both metals, which could explain the lesser tolerance for cobalt. Nickel appears to be essential for the plant to tolerate high cobalt concentrations. Further studies intending to develop agronomic practices are needed to determine the viability of Rinorea cf. bengalensis for nickel-cobalt agromining. [ABSTRACT FROM AUTHOR]

As a main element in the hard metal industry, cobalt is one of the major components of human metal implants. Cobalt-containing implants, especially joint prostheses used for artificial joint replacement, can be corroded due to the complex physiological environment in vivo, producing a large number of nanoscale cobalt particles (Cobalt Nanoparticles, CoNPs). These CoNPs can be first accumulated around the implant to cause adverse local reactions and then enter into the blood vessels followed by reaching the liver, heart, brain, kidney, and other organs through systematic circulation, which leads to multi-system toxicity symptoms. To ensure the long-term existence of cobalt-containing implants in the body, it is urgently required to find out a safe and effective detoxification drug. Herein, we have demonstrated that CoNPs could induce the ferroptosis-like cell death through the enhancement of intracellular reactive oxygen species (ROS) level, cytoplasmic Fe2+ level, lipid peroxidation, and consumption of reduced glutathione (GSH) as well as inhibition of glutathione peroxidase 4 (GPX4) activity. Importantly, α-lipoic acid (ALA), a natural antioxidant with the capability to scavenge free radicals and chelate toxic metals, was found to efficiently alleviate the adverse effects of CoNPs. The present study illustrates a new mechanism of CoNPs mediated by ferroptosis-like cytotoxicity and discloses an effective method for the detoxification of CoNPs by employing the natural antioxidant of ALA, providing a basis for further in vivo detoxification study. [ABSTRACT FROM AUTHOR]

Excess cobalt may lead to metallosis, characterized by sensorineural hearing loss, visual, and cognitive impairment, and peripheral neuropathy. In the present study, we sought to address the molecular mechanisms of cobalt-induced neurotoxicity, using Caenorhabditis elegans as an experimental model. Exposure to cobalt chloride for 2 h significantly decreased the survival rate and lifespan in nematodes. Cobalt chloride exposure led to increased oxidative stress and upregulation of glutathione S-transferase 4. Consistently, its upstream regulator skn-1 , a mammalian homolog of the nuclear factor erythroid 2-related factor 2, was activated. Among the mRNAs examined by quantitative real-time polymerase chain reactions, apoptotic activator egl-1 , proapoptotic gene ced-9 , autophagic (bec-1 and lgg-1), and mitochondrial fission regulator drp-1 were significantly upregulated upon cobalt exposure, concomitant with mitochondrial fragmentation, as determined by confocal microscopy. Moreover, drp-1 inhibition suppressed the cobalt chloride-induced reactive oxygen species generation, growth defects, and reduced mitochondrial fragmentation. Our novel findings suggest that the acute toxicity of cobalt is mediated by mitochondrial fragmentation and drp-1 upregulation. [ABSTRACT FROM AUTHOR]

Purpose: Cobalt exposure is known to cause adverse effects on health. A major use of cobalt is in the manufacture of hard metal. Exposure can lead to asthma, hard metal lung disease, contact allergy and increased risk of cancer. Cobalt is mainly absorbed from the pulmonary tract, however penetration through skin may occur. The relationships between exposure to inhalable cobalt in air and on skin and the uptake in blood and urine will be investigated, as well as the association between dermal symptoms and dermal exposure. Methods: Cobalt exposure in 71 workers in hard metal production facilities was measured as inhalable cobalt in the breathing zone and cobalt found on skin with acid wash. Uptake of cobalt was determined with concentrations in blood and urine. Correlations between exposure and uptake were analysed. Results: Inhalable cobalt in air and cobalt in blood and urine showed rank correlations with coefficients 0.40 and 0.25. Cobalt on skin and uptake in blood and urine presented correlation coefficients of 0.36 and 0.17. Multiple linear regression of cobalt in air and on skin with cobalt in blood showed regression coefficients with cobalt in blood (β = 203 p < 0.0010, and β = 0.010, p = 0.0040) and with cobalt in urine (β = 5779, p = 0.0010, and β = 0.10, p = 0.60). Conclusions: Our data presents statistically significant correlations between exposure to cobalt in air with uptake of cobalt in blood and urine. Cobalt on skin was statistically significant with cobalt in blood but not with urine. [ABSTRACT FROM AUTHOR]

During bioleaching of Cobalt from waste lithium-ion batteries, the biooxidation activity of acidophilic bacteria is inhibited by a high concentration of Co ion in the liquid phase. However, the mechanism for Co2+ toxicity to acidophilic bacteria has not been fully elucidated. In this study, the effects of Co2+ concentration on the biooxidation activity for Fe2+, intracellular reactive oxygen species (ROS) level and antioxidant defense systems in a mixed-culture of acidophilic bacteria (MCAB) were investigated. The results showed that the biooxidation activity of the MCAB was inhibited by Co2+. Furthermore, it was indicated that the intracellular ROS contents of the MCAB under conditions of 0.4 M and 0.6 M Co2+ were 2.60 and 3.34 times higher than that under the condition of 0 M Co2+. The increase in intracellular malondialdehyde content indicated that the oxidative damage was induced by Co2+. Moreover, the antioxidant systems in MCAB were affected by Co2+. It was observed that the Co2+ exposure increased the catalase and glutathione peroxidase activities while reducing the superoxide dismutase activity and the intracellular glutathione (GSH) content. It was found that an exogenous GSH supplementation eliminated excess intracellular ROS and improved the biooxidation activity of the MCAB. [ABSTRACT FROM AUTHOR]

The replacement of a native hip joint by a metal‐on‐metal prosthesis may induce deleterious inflammatory side effects that are associated with the release of wear particles and metal ions. These events are referred to the adverse reaction to metal debris (ARMD) and the adverse local tissue reaction (ALTR). While wear particles seem involved in ARMD, the role of metal ions in ALTR and their impact on myoblasts, located in the prosthesis vicinity, has not been fully identified. To clarify this issue we investigated, using an in vitro culture system, the effect of cobalt and/or chromium ions (Co2+ and/or Cr3+) on human myoblast proliferation, cellular differentiation, and inflammatory marker expression. Freshly isolated human myoblasts were cultured in media supplemented with graded concentrations of Co2+ and/or Cr3+. Co2+ induced a concentration‐dependent decrease of both myoblast viability and myogenic differentiation while Cr3+ did not. Co2+ or Co2+/Cr3+ also induced the upregulation of ICAM‐1, whereas HLA‐DR expression was unaffected. Moreover, allogenic monocytes induced the synergistic increase of Co2+‐induced ICAM‐1 expression. We also found that Co2+ stabilized HIF‐1α and increased TLR4, tumor necrosis factor‐alpha (TNF‐α), and interleukin 1β (IL‐1β) expression in a dose and time‐dependent manner in human myoblasts. This study showed that Co2+, but not Cr3+, was toxic toward myoblasts and induced, in the surviving cells, expression of inflammatory markers such as ICAM‐1, TLR4, TNF‐α, and IL‐1β. This suggests that Co2+, most efficiently in the presence of monocytes, may be a key inducer of ALTR, which may, if severe and long‐lasting, eventually result in prosthesis loosening. [ABSTRACT FROM AUTHOR]

Enzyme mimics have been widely used as alternatives to natural enzymes, owing to their high stability and low cost. However, the activity and atom economy of enzyme mimics still need to be improved. Herein, we report the boosting effects of amino acids, peptides and proteins on the peroxidase‐like activity of Co2+. Among 20 amino acids, tryptophan (Trp) enhanced the activity of Co2+ approximately 8 times and was identified as the best stimulator. The study revealed the synergy of amino acids‐based species and HCO3− for efficient catalysis. Co2+ is proposed to bind simultaneously to HCO3− and Trp, and to form a ternary catalyst which facilitates the generation of reactive oxygen species. Based on the selective boosting by Trp, a simple and low‐cost Co2+ sensor with high sensitivity was developed, which showed a linear range of 10–300 μM and a limit of detection of 0.4 μM for Co2+. [ABSTRACT FROM AUTHOR]

Objective: It has been suspected that cobalt is toxic to the heart. It can cause cardiotoxicity in heavily exposed humans and in experimental systems. The issue of interest for this study is whether cobalt also affects the myocardium at occupational exposure levels. Methods: To study the effect of occupational cobalt exposure on the heart, we conducted a follow-up of workers at a cobalt production plant. The workers' hearts had been examined by echocardiography in 1999–2000. Altogether 93 exposed and 49 non-exposed workers examined in 1999–2000 were re-examined in 2006. Occupational history and health data were collected with a questionnaire. Blood pressure was measured, and electrocardiography (ECG), laboratory tests, Holter registration, and echocardiography were conducted for all participants. Analysis of covariance (ANCOVA) was used to analyse the data. Results: No differences were found between the exposed and unexposed groups for any of the echocardiographic parameters in 2006. There were no differences in the laboratory values, the ECG parameters, or the results of the Holter registration of the exposed and unexposed workers. Conclusions: Although the previous results in 2000 suggested an association between cumulative exposure to cobalt and echocardiographic findings, the results of this new cross-sectional study with a tissue Doppler 6 years later did not confirm the association in the present cohort. If cobalt exposure affects heart muscle functions at this exposure level, the effects are smaller than those caused by physiological changes due to ageing, medication, and traditional cardiovascular risk factors, such as elevated blood pressure. [ABSTRACT FROM AUTHOR]

Based on the wide use of cobalt substances in a range of important technologies, it has become important to predict the toxicological properties of new or lesser-studied substances as accurately as possible. We studied a group of 6 cobalt substances with inorganic ligands, which were tested for their bioaccessibility (surrogate measure of bioavailability) through in vitro bioelution in simulated gastric and intestinal fluids. Representatives of the group also underwent in vivo blood kinetics and mass balance tests, and both oral acute and repeated dose toxicity (RDT) testing. We were able to show a good correlation between high in vitro bioaccessibility with high in vivo bioavailability and subsequent high in vivo toxicity; consequently, low in vitro bioaccessibility correlated well with low in vivo bioavailability and low in vivo toxicity. In vitro bioelution in simulated gastric fluid was the most precise predictor of the difference in the oral RDT lowest observed adverse effect levels of 2 compounds representing the highly and poorly bioaccessible subset of substances. The 2 compounds cobalt dichloride hexahydrate and tricobalt tetraoxide differed by a factor of 440 in their in vitro bioaccessibility and by a factor of 310 in their RDT lowest observed adverse effect level. In summary, this set of studies shows that solubility, specifically in vitro bioelution in simulated gastric fluid, is a good, yet conservative, predictor of in vivo bioavailability and oral systemic toxicity of inorganic cobalt substances. Bioelution data are therefore an invaluable tool for grouping and read across of cobalt substances for hazard and risk assessment. [ABSTRACT FROM AUTHOR]

The determination of Cd, Co, Cr, Cu, Fe, Na, Zn, and Pb by inductively coupled plasma-optical emission spectrometry (ICP OES) was performed on dry matter and decoctions of the medicinal plants Cordia salicifolia, Chiococca alba (L.) Hitchc., and Echites peltata used as an appetite suppressant and diuretic in Brazil. The accuracy of the measurements was analyzed by the spike recovery test. Results showed that the concentration of these seven metals (Cd, Co, Cr, Cu, Fe, Na, and Zn) in dry plant samples is below the oral concentration of elemental impurities established by the United States Pharmacopoeia Convention (USP). However, there are no concentration limits for Fe, Na, and Zn established by the USP in drug substances and excipients. Levels higher than the recommended value by the USP were observed for Pb and the lowest for Cd, Co, Cr, and Cu, both in dried plant samples and their decoctions. In the decoctions prepared from these plants were found elements such as Cd, Co, Cr, Cu, Fe, Na, Zn, and Pb. In the decoction prepared from 40 g C. salicifolia leaves and 40 g C. alba wood, the content of Cd is above the oral daily exposure value set by the USP. Hazard index (HI) for decoctions prepared from these plants exceeded the threshold (1). Given the uncertainties associated with the estimates of toxicity values and exposure factors, futures researches should address the possible toxicity in humans. Uncontrolled selling and long-term ingestion of medicinal plants can cause toxicity and interfere with the effect of drugs. Limited knowledge on the interaction potential of medicinal plants poses a challenge and public health problem in Brazil and other countries. [ABSTRACT FROM AUTHOR]

To overcome the problem that ferrous complexes are easily oxidized by O2 and then lose NO binding ability in the chemical absorption-biological reduction (CABR) process, cobalt(II)-histidine [Co(II)His] was proposed as an alternative. To evaluate the applicability of Co(II)His, the effects of CoHis absorbent on the aerobic denitrification by Paracoccus versutus LYM were investigated. Results indicated that His significantly promoted nitrite reduction. The inhibition effects of CoHis absorbent could be substantially alleviated by increasing the initial His/Co2+ to 4 or higher. CoHis with concentrations of 4, 8, 12, 16 and 20 mM presented no distinct effect on nitrite reduction, but slightly inhibited the reduction of nitrate, resulting in longer lag of nitrate reduction, and obviously promoted the growth of strain LYM. In the presence of 5, 10, 15 and 20 mM CoHis absorbent, the main denitrification product was N2 (not less than 95.0%). This study is of significance in verifying the applicability of Co(II)His in the CABR process, and provides a referable CoHis absorbent concentration as 20 mM with an initial His/Co2+ of 4 for the future experiments. [ABSTRACT FROM AUTHOR]