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This document provides information on the topic of cobalt toxicity in patients with metal-on-metal (MoM) hip implants. Cobalt toxicity can lead to various symptoms and complications, including peripheral neuropathy, hearing loss, cardiomyopathy, and hypothyroidism. The diagnosis involves elevated cobalt levels, confirmed findings consistent with cobalt toxicity, and exclusion of other causes. Treatment options include symptomatic management, chelation therapy, and revision of the MoM hip implant. Early detection is important for better outcomes. [Extracted from the article]

Frequent discharge of cobalt in ionic form (Co2+) during industrial processes is contaminating agricultural soil through the addition of industrial effluent. Cobalt is beneficial element in trace amounts but its higher concentrations in soil severely damage the growth and development of plants. In this two-year study, the pre-selected sublethal level (0.5 mM) concentration of Co2+ was applied in soil to induce toxicity on two elite maize (Zea mays L.) hybrids ('Hycorn11plus' and 'P-1429'). To encounter the toxic effects of selected sub-lethal (0.5 mM) Co2+ level (applied using CoCl2·6H2O), pre-optimized levels of three stress protective chemicals (SPCs) i.e., ascorbic acid (0.5 mM), salicylic acid (0.5 mM) and thiourea (1.0 mM) were foliar sprayed. The Co2+ and SCPs treatments were applied 10 days after seedling emergence. After ten days of treatment application, the data were recorded for the growth, nutrients and leaf water status. The shoot and root dry weights and shoot-to-root (S/R) ratio were substantially reduced by the Co2+ stress. Co2+ intoxication also enhanced the leaf water loss (LWL) while relative water contents (RWC) were reduced in Co2+ stressed plants. The Co2+ treatment reduced the intake of nitrate-N, sulfate-S, phosphate-P, K+, Ca2+, Mg2+, Zn2+, and Fe2+ contents significantly both in the shoot and root. However, from the correlation matrix, it was noted that the foliar spray of SPCs effectively alleviated the Co2+damage by preventing the influx of Co2+ ions and enhanced the growth, water and nutrient contents except for LWL. From the reduced RWC and shoot and root nutrient contents, as well as increased LWL and Co2+ contents, it is evident that Co2+ interfered with either the function or structure of water and ion-transport systems located on the plasma lemma and tonoplast of root cells. AsA was more effective among the foliar applied SPCs due to its multiple metabolic roles in plants. The foliar spray of SPCs improved the root mass and tendency to absorb essential nutrients under Co2+toxicity indicating an intimate communication between shoot and root. The use of SPCs at the selected levels is a pragmatic strategy to counteract the Co2+ damage to maize in the marginally contaminated areas. [ABSTRACT FROM AUTHOR]

Cobalt (Co2+) is a beneficial microelement for plants but toxic to metabolism in higher amounts. This study determined the influence of sublethal Co2+ level (0.5 mM) on the growth of maize (Zea mays L.) hybrids; Hycorn 11 plus (Co2+ sensitive) and P-1429 (Co2+ tolerant) and its alleviation with foliar spray of pre-optimized levels of stress protective chemicals (SPCs), i.e., salicylic acid (SA, 0.5 mM), thiourea (TU, 1.0 mM), and ascorbic acid (AsA, 0.5 mM) applied at seedling, vegetative, and late vegetative stages. Plants were harvested at early vegetative, late vegetative, and silking stages. Co2+ stress caused a decrease in shoot and root length, dry weight, leaf area, and culm diameter, reduced the activities of enzymatic antioxidants and concentrations of AsA and soluble phenolics more in root than shoot, but P-1429 was more tolerant of Co2+ than Hycorn 11 plus. SPCs spray alleviated oxidative damage by enhancing the antioxidant activity, AsA and soluble phenolics, sulfate-S and nitrate–N contents, which were significantly increased in roots than in shoots; P-1429 displayed better response than Hycorn 11 plus. Principal component analysis and correlation matrix revealed the profound roles of SPCs spray in improving Co2+ resistance in root leading to robust growth of hybrids. AsA was highly promising in reducing Co2+ toxicity while vegetative and silking stages were more sensitive. Results revealed that after translocation to root, the foliar-applied SPCs had individualistic modes of action in mitigating Co2+ toxicity on roots. In crux, the metabolism and phloem transport of the SPCs from shoot to root are plausible mechanism for Co2+ tolerance in maize hybrids. [ABSTRACT FROM AUTHOR]

Safety concerns regarding cobalt-containing metal alloy hip prosthetics (Co-HP) have resulted in product recalls, a medical device alert, and issuance of guidance for clinicians. Recently, cases of suspected prosthetic hip-associated cobalt toxicity (PHACT) from Co-HP have been reported. Although little is known about suspected PHACT, these patients may be referred to medical toxicologists for evaluation and management recommendations. We searched MEDLINE, EMBASE, and unpublished abstracts from toxicology scientific meetings for references relevant to PHACT. Authors independently screened publications for inclusion criteria: publication in English, human study population, subject(s) are symptomatic (except for isolated hip pain), and cobalt values in any matrix (blood, serum, urine, CSF, synovial fluid) available for review. Data from 10 cases are reviewed. Patients with suspected PHACT had findings consistent with cobalt toxicity, including thyroid, cardiac, and neurologic dysfunction. Signs and symptoms appeared between 3 and 72 months after arthroplasty (median 19 months). Neurologic symptoms were most common. Ancillary testing varied considerably. All patients had elevated cobalt levels in one or more matrices. Enhanced elimination was attempted in 27 % of patients. At this time, the information currently available regarding patients with suspected PHACT is inadequate to guide clinical decision making. No consensus has been reached regarding the management of Co-HP patients with systemic symptoms. Indications for chelation have not been established and require further study. Improved case definitions, improved surveillance, and controlled studies are needed to elucidate the scope of this problem and guide future investigations. [ABSTRACT FROM AUTHOR]

Characteristics of fungal species tolerant to high levels of metals in natural environment can be amplified by isolation and selection of resistant mutants. Step-by-step culturing led to identification of highly stable Co-resistant (CoR) mutants of A. nidulans. Based on two distinct morphological features, Co-resistant mutants were categorized as CoRI and CoRII. The two mutants varied in their growth behavior and colony morphology that were reflected in supplemented as well as unsupplemented growth media over the generations. As compared to the CoRI, CoRII mutant exhibited sparse mycelia and conidiation but secreted higher amount of melanin. CoR mutants could tolerate up to 2.5mM Co in the medium, however, required a threshold concentration of 0.25mM Co for optimal growth and germination. Absence of Co in the medium caused a stressful situation for the CoR mutants and led to the secretion of a white extracellular precipitate found to be a glycoprotein. In response to interactions with Co-ions, CoR mutants produced oxalic acid and bioprecipitated Co as Co-oxalate providing scope for metal reclamation as well as oxalic acid extraction. The mutants could help to recover the insoluble Co-oxalate salt from aqueous solutions by entrapping it in their growing mycelial meshwork. [ABSTRACT FROM AUTHOR]

Background: Hydroxocobalamin has been shown to be a rapid and powerful antidote in acute cyanide poisoning and to prevent cyanide poisoning during sodium nitroprusside administration. This cobalt-containing compound has been shown to be devoid of significant immediate side effects during acute administration. However, its potential delayed toxicity related to cobalt accumulation in tissue remains unknown. Therefore, we evaluated the toxicity of hydroxocobalamin as compared with that of cobalt salts on rat cardiac and diaphragmatic muscles. Methods: For a 21-day period, rats were treated intraperitoneally with either hydroxocobalamin (70 mgkg per day, n=14) cobalt chloride hexahydrate (12 mg kg per day, n=14) or saline ( n=10). Hydroxocobalamin and cobalt chloride groups received equimolar doses of cobalt. We studied: (1) the mechanical properties of isolated left ventricular papillary muscles and diaphragmatic strips, (2) the cardiac and diaphragmatic cobalt tissue concentrations, and (3) the myocardial histological aspect. Results: During the study period, no significant increase in body weight was noted in the cobalttreated group (−4±1%), which was in contrast to the hydroxocobalamin-treated group (+21±2%) and the saline-treated group (22±2%). Compared with controls, the mechanical properties of cardiac and diaphragmatic muscles were unchanged after either hydroxocobalamin or cobalt salt treatments, and myocardial histological characteristics were similar in all groups. Conversely, large amounts of cobalt deposit were observed in the cobalt-treated group in both the diaphragm (41.90±16.30 vs 0.70±0.40 μmol μg in the control group, P<0.001). After hydroxocobalamin administration, cobalt concentrations were significantly lower in the diaphragm (25.10±16.50 μmol μg, P<0.001 vs cobalt-treated group) and the myocardium (4.50±1.20 μmol μg, P<0.001 vs cobalt-treated group). Conclusion: These results indicate that repeated administration of hydroxocobalamin was devoid of significant diaphragmatic and cardiac muscle toxicity and therefore remains a safe antidote for acute cyanide poisoning. [ABSTRACT FROM AUTHOR]

Chemical overexposure is a growing environmental risk factor for many medical issues. Cobalt toxicity from environmental, industrial, and medical exposure has previously been linked to neurological impairment. Hence, the current study looked into the neuroprotective potential of curcumin, a natural polyphenol contained in the spice turmeric, against cobalt-induced neurotoxicity. Adult rats were randomly divided into six groups as follows: control, 40 mg/kg cobalt chloride (CoCl2) only, 240 mg/kg curcumin only, 120 mg/kg or 240 mg/kg curcumin, or 100 mg/kg vitamin C co-administered with CoCl2. The administration was via oral route daily for 4 weeks. After that, neurobehavioral tests were undertaken to evaluate short-term spatial memory. Biochemical investigation was performed to determine the hippocampal levels of status via measures of SOD, CAT, GST, and LPO. Furthermore, immunohistochemical assessment of the expression of GFAP and Nrf2 in the hippocampus was carried out. In the CoCl2 group, the results showed altered behavioral responses, a decrease in antioxidant activities, increased expression of GFAP and the number of activated astrocytes, and decreased immunoexpression of Nrf2. These effects were mitigated in the curcumin- and vitamin C–treated groups. These results collectively imply that curcumin enhances memory functions in rats exposed to cobalt possibly by attenuating oxidative responses, mitigating astrocytosis, and modulating Nrf2 signaling. [ABSTRACT FROM AUTHOR]

The use of wastewater in irrigation weakens the beneficial properties of the soil and leads to a threat to food safety standards. The present research was designed to explore the cobalt toxicity associated with the ingestion of wastewater irrigated wheat. Wheat plants of five different varieties were collected from 7 different sites of Punjab, Pakistan, which were irrigated with three different sources of water. The sampling was done in two cropping years. The cobalt values in water, soil and wheat samples (root, shoot, grain) ranged from 0.46 to 1.24 mg/l, 0.15 to 1.20, 0.29 to 1.30, 0.08 to 0.76 and 0.12 to 0.57 mg/kg, respectively. All the water samples showed high cobalt concentration than the maximum permissible value. However, all the soil and wheat plant samples were found within the maximum allowable range. The high cobalt concentration in irrigating water showed that the continuous usage of such type of water may lead to cobalt toxicity in living organisms with the passage of time and may results in severe health risks. [ABSTRACT FROM AUTHOR]

Introduction: There have been concerns about prosthesis failure and the potential for systemic toxicity due to release of cobalt and chromium from metal-on-metal hip joint prostheses (MoM-HP). There is conflicting evidence on whether there is a correlation between higher cobalt and chromium concentrations and systemic toxicity. Methods: We undertook a retrospective review of consecutive patients with MoM-HP referred for outpatient review in toxicology clinics in London, UK, and in the USA recorded in the Toxicology Investigators Consortium (ToxIC) Registry from June 2011 to June 2015. Results: Thirty-one cases were identified; the median (IQR) serum cobalt concentration was 10.0 (3.8-32.8) mcg/L, and the median (IQR) serum chromium concentration was 6.9 (3.7-18.7) mcg/L. Twenty-three (74.2%) had symptoms, most commonly lethargy, hearing loss, and tinnitus. The odds ratios of symptomatic/asymptomatic patients for metal ion concentrations above/below 7 mcg/L were 1.87 (95% CI 0.37-9.57, p = 0.45) and 0.60 (95% CI 0.10-3.50, p = 0.57) for cobalt and chromium, respectively. Two (6.5%) patients with systemic cobalt toxicity had median (IQR) serum cobalt concentrations significantly higher than those without systemic features (630.4 [397.6-863.2] mcg/L versus 9.8 [2.9-16.4] mcg/L; p = 0.017). However, overall, there were no differences between cobalt ( p = 0.38) or chromium ( p = 0.92) concentrations between symptomatic and asymptomatic patients and no clinical features or investigation results correlated with cobalt or chromium concentration. Conclusion: Two (6.5%) of 31 individuals referred for assessment of MoM-HP were diagnosed with systemic cobalt toxicity. However, despite a high prevalence of reported symptoms, neither symptoms nor investigation results correlated with serum cobalt or chromium concentrations. [ABSTRACT FROM AUTHOR]

Cobalt-induced cardiomyopathy is a well-known but uncommon disease, and the physician must maintain a high index of suspicion in order to make a timely diagnosis. We report two patients with cobalt-induced cardiomyopathy. Both patients developed progressively worsening symptoms of cobalt toxicity following revision of a fractured ceramic-on-ceramic total hip replacement to a metal-on-polyethylene bearing. In both patients, echocardiography showed LV hypertrophy, biventricular systolic dysfunction, and a large amount of pericardial effusion. Due to decompensated heart failure, both patients were initially considered candidates for heart transplantation. One patient was diagnosed with cobalt-induced cardiomyopathy before transplantation. He received cobalt chelation therapy and revision surgery, which led to complete recovery of heart function. In the other patient, the diagnosis was not made until the time of heart transplantation. The gross examination of the explanted heart revealed typical features of cobalt cardiotoxicity, which was then diagnosed as cobalt-induced cardiomyopathy. These cases emphasise the importance of early diagnosis and prompt treatment of cobalt intoxication. [ABSTRACT FROM AUTHOR]

Cobalt intoxication is a rare complication of joint arthroplasty with a metal-on-metal prothesis or metal implants after broken ceramic implants. Patients with metal components should be monitored closely for complications. The awareness for the wide range of clinical pictures of this cobalt intoxication should be increased. We here describe the clinical presentation, diagnostic and therapeutic work-up of a 70-year-old patient with a cobalt metallosis. The patient presented with a progressive deterioration of vision and hearing, axonal sensorimotor polyneuropathy and cataract. The extensive work-up resulted in the diagnosis of a cobalt metallosis as a complication of a metal hip prosthesis. Cobalt intoxication, especially after metal-on-metal total joint arthroplasty, is a rare complication; however, there have been several reports of similar cases. It is therefore recommended to avoid the implantation of a metal-on-metal prothesis or metal implants after broken ceramic implants as in this case whenever possible. Patients with exclusively metal components should be monitored closely for complications. [ABSTRACT FROM AUTHOR]

Objectives: To define the vitamin B12 levels and other micronutrients status in severe acute malnutrition (SAM) children. Methods: This was a prospective hospital based cross-sectional study. Inclusion criteria: Children with severe acute malnutrition as per WHO criteria. Exclusion criteria: (i) Pernicious anemia (ii) Autoimmune gastritis (iii) SAM children on exclusive vitamin B12 supplementation. All enrolled children underwent a detailed clinical history, general physical examination with more emphasis on clinical features of vitamin B12 and other micronutrients deficiencies. Three ml of venous blood was collected to estimate vitamin B12 and other micronutrients. Primary outcome was percentage of deficiency of serum vitamin B12, zinc, copper, selenium, manganese, molybdenum and cobalt in SAM children. Results: Fifty children were included in the study. The mean age of children was 15.60±12.90 mo with male to female ratio 0.85:1. The common clinical presentation in order of frequency were upper respiratory infection (URI) symptoms 35 (70%), hepatomegaly 24 (48%), Hyperpigmentation 17 (34%), angular cheilitis 14 (28%), tremors 11 (22%), edema 07 (14%), and hypotonia 05 (10%). Anemia was found in 44 (88%) children. Prevalence of vitamin B12 deficiency was 34%. Other micronutrient deficiencies observed were cobalt 24 (100%), copper 05 (12%), zinc 04 (9.5%), and molybdenum 03 (12.5%). No statistical significance was found between clinical symptoms and levels of vitamin B12 with different age and sex. Conclusions: Prevalence of low vitamin B12 and cobalt were more common than other micronutrients. [ABSTRACT FROM AUTHOR]

Metal-on-metal hip arthroplasty has been performed with increasing frequency throughout the world, particularly in younger and more active patients, including women of childbearing age. The potential toxicity of cobalt exposure on fetus is concerned since cobalt ions generated by metal-on-metal bearings can traverse the placenta and be detected in fetal blood and amniotic fluid. This study examined the effects of cobalt exposure on early embryonic development and the mechanisms underlying its toxicity. Zebrafish embryos were exposed to a range of cobalt concentrations (0-100 mg/L) between 1 and 144 h postfertilization. The survival and early development of embryos were not significantly affected by cobalt at concentrations <100 μg/L. However, embryos exposed to higher concentrations (>100 μg/L) displayed reduced survival rates and abnormal development, including delayed hatching, aberrant morphology, retarded growth, and bradycardia. Furthermore, this study examined oxidative stress and apoptosis in embryos exposed to cobalt at concentrations of 0-500 μg/L. Lipid peroxidation levels were increased in cobalt-treated embryos at concentrations of 100 and 500 μg/L. The mRNA levels of catalase, superoxide dismutase 2, p53, caspase-3, and caspase-9 genes were upregulated in a dose-dependent manner. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays also revealed abnormal apoptotic signals in the brain, trunk, and tail when treated with 500 μg/L cobalt. These data suggest that oxidative stress and apoptosis are associated with cobalt toxicity in zebrafish embryos. [ABSTRACT FROM AUTHOR]

In the current study, six bacterial types, isolated from spent nuclear fuel (SNF) pool facility, were investigated for their ability to sequester heavy metals (cobalt and nickel). Biofilm formation by the six bacterial isolates, viz., Bacillus subtilis, Staphylococcus species, Staphylococcus arlettae, Staphylococcus epidermidis, Staphylococcus auricularis, and Chryseobacterium gleum, were assayed, and they were found to have significant biofilm forming property. Their biofilms were characterised using confocal scanning laser microscopy, and their potential to accumulate Co2+ and Ni2+ from bulk solutions was analysed with respect to time. A comparative assessment of bioaccumulation capacity was done using biofilms, planktonic cells, and live vs dead cells. The strains accumulated Co2+ and Ni2+ in the range of 4 × 10−4 to 1 × 10−5 g/mg of cell biomass. It is interesting to note that dead biomass also showed significant removal of the two metal ions, suggesting an alternative process for metal removal. This study suggests that hostile environments can be a repertoire of putative bacterial species with potential heavy metals and other contaminants remediation properties. [ABSTRACT FROM AUTHOR]

This study investigated the impact of cobalt and cesium stresses on two hulless barley varieties through a hydroponic experiment. The plants were exposed to 200 μM cobalt chloride (Co), 200 μM cesium chloride (Cs), or with concurrent exposure to 100 μM Co + 100 μM Cs. The findings revealed that exposure to Co and Cs, either alone or in combination, caused a substantial reduction in plant growth and weight. Interestingly, the hulless barley seedlings were found to be more resilient to Cs stress, attributed to its lower Cs enrichment factor. The stressed seedlings demonstrated increased oxidative stress levels (malondialdehyde, proline, and content), but also displayed increased activity of antioxidant enzymes (POD and SOD), active oxygen scavenging capacity (GSH and GSSG content), and gene expression (GSH2, POD and SOD), reflecting a plant defense mechanism. Moreover, the expression of PAL and P5CS genes was significantly enhanced in seedlings under Co, Cs, and (Co + Cs) treatments, providing a basis for the physiological mechanism of heavy metal resistance in hulless barley. The results of this study provide valuable insights into the mechanisms of heavy metal resistance in hulless barley, indicating the plant's potential for phytoremediation. [ABSTRACT FROM AUTHOR]

The present systematic review investigated the concentration of chromium (Cr) and cobalt (Co) in serum in patients who have undergone total hip arthroplasty (THA). The first outcome of interest was to investigate the mean concentration in serum of Cr and Co using different material combinations and to verify whether their concentrations change significantly using different patterns of head and liner in THA. The second outcome of interest was to investigate whether the time elapsed from the index surgery to the follow-up, BMI, sex, and side exert an influence on the mean concentration of Cr and Co in serum in patients who have undergone THA. The following material combinations were investigated (head-liner): Ceramic-Co Cr (CoCr), CoCr-CoCr, CoCr-Polyethylene, CoCr high carbide-CoCr high carbide. Data from 2756 procedures were retrieved. The mean length of follow-up was 69.3 ± 47.7 months. The ANOVA test evidenced good comparability in age, length of follow-up, BMI, and sex (P > 0.1). In patients who have undergone THA, the mean concentration in the serum of Co ranged between 0.5 µg/L and 3.5 µg/L, and the mean concentration of Cr from 0.6 to 2.6 µg/L. The difference in the concentration of Co and Cr in serum is strictly related to the implant configuration, with the coupling CoCr-CoCr showing the highest and CoCr-Polyethylene showing the lowest concentration. Patient characteristics, BMI, sex, side and the time elapsed from the index surgery to the last follow-up did not exert a significant influence on the concentration of Co and Cr in serum in patients who have undergone total hip arthroplasty (THA). [ABSTRACT FROM AUTHOR]

Cobalt (Co) bioaccumulation, contamination, and toxicity in the soil environment, plant growth, and cattles' health are becoming a severe matter that can cause unembellished consequences in environmental safety and human health. The present research was conducted for the assurance of cobalt (Co) amassing in three forage plant species (Zea mays, Sorghum bicolor, Trifolium alaxandrium), from four ecological sites, and sewage water and in buffaloes blood was investigated. The analysis of variance showed significant differences for Co concentration in the soil and sewage water collected from all ecological sites. Meanwhile, summer and winter seasons and forage ecotypes significantly influenced the quantity of Co. The forage pastures also vary significantly in the concentration of Co in the above-ground parts. The highest Co level was present in Trifolium alaxandrium at ecological site-5. Cobalt taken from wastewater had a higher concentration in Trifolium alaxandrium during the winter. The samples which are collected from site-V and site-IV have the maximum concentration of Co because these areas receive highly contaminated water for irrigation. Cobalt tends to be bioaccumulated in the food chain and can cause serious problems in humans and animals. Bioaccumulation of cobalt in collected samples could be accredited to anthropogenic activities. Pollution load index values for all samples fell in the range below 1. The health risk index indicated the probability of health damage caused by the ingestion of contaminated fodder. An increase of Co concentration in soil, fodder, and blood owing to wastewater irrigation to crops was indicated as an outcome of this investigation. The results indicate that the Co toxicity in forage crops is attributed to Co bioaccumulation, transfer, and pollution load in the soil–water-cattle triangle. Efforts should be extended to avoid contamination of the food chain via Co-rich sewage water. Other nonconventional water resources should be used for forage irrigation. [ABSTRACT FROM AUTHOR]

Background: Corrosion of stem-cobalt/chromium (Co/Cr) head interface and subsequent systemic Co ion complication have been a clinical concern after total hip arthroplasty (THA). The aim of this study is to investigate correlation between type of femoral head and blood Co ion level.Methods: One hundred four patients with THA using accolade TMZF and Co/Cr femoral head (32-mm; 55 cases, 36-mm; 20 cases, dual mobility system (DM) with 22.2 or 28-mm inner head; 29 cases) participated in this study, and blood Co ion concentration test was performed in patients a minimum of four years after THA.Results: DM group was significantly older than 32-mm and 36-mm group (DM: 73.9 ± 4.6, 32-mm: 63.3 ± 8.5, 36-mm: 66.8 ± 10.5). The median (interquartile range) blood Co concentration of each group was 32-mm group 0.26 µg/L (0.69), 36-mm group; 0.21 µg/L (0.30); and DM group 0.21 µg/L (0.13). There was a significant difference of Co concentration between DM and 32-mm group (p = 0.023). Abnormal values of the blood Co concentration (> 1 µg/L) were observed in the 32-mm group; 12 cases (21.8%), 36-mm group; 2 cases (10.0%); and DM group; 0 case (0%) (p = 0.018).Conclusions: Co blood concentration differed among the different sizes of Co/Cr femoral head. THA using DM is a safe option with low risk of complication from cobalt ion if it is used for elderly patients. [ABSTRACT FROM AUTHOR]

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]

Purpose: The effect of elevated serum cobalt on the human visual system has not yet been established. In light of recent reports of visual problems with elevated cobalt in association with hip prostheses, this review examines the literature for evidence regarding the effects of cobalt on human visual function. Methods: A systematic literature review was undertaken in July 2013. The electronic databases of PubMed (1955 to July week 1 2013), Cochrane Library and EMBASE were searched. Only human studies or case reports written in English were included. Results: Eight case reports were identified. Five case reports involved patients with metal hip arthroplasties, two cases involved patients exposed to environmental cobalt, and one case involved a patient treated medically for anaemia with cobalt chloride. No human prospective studies were identified. Conclusions: Several case reports showed that high serum cobalt may be associated with both irreversible and reversible visual loss, optic neuropathy and atrophy, electrophysiological evidence of abnormal retinal and retinal pigment epithelium function and fluorescein angiographic evidence of abnormal choroidal perfusion. [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]

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]

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]

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]

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]

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]

The wide use of cobalt (Co) in food, industry, and medical devices requires full elucidation of its biological effects on tissues and organs. The aim was to assess serum metabolic alterations in immature mice after subchronic exposure to CoCl2. Pregnant ICR mice were subjected to a daily dose of 75 mg cobalt chloride/kg body weight (CoCl2x6H2O) 2–3 days before they gave birth, and treatment continued until days 25 and 30 after delivery. The compound was dissolved in and obtained with regular tap water. ICP-DRC-MS analysis showed significantly elevated serum Co2+ and diverse alterations in metabolic parameters of 25- and 30-day-old pups after exposure to CoCl2. Cholesterol and urea levels were significantly elevated in day 25 mice while HDL-C and LDL-C were reduced. In day 30, Co-exposed mice LDL-C and triglycerides were significantly increased while the total cholesterol level remained unchanged. Alkaline phosphatase was significantly reduced in day 25 Co-exposed mice. Blood glucose level of Co-exposed mice remained close to the untreated controls. Total protein content was slightly increased in day 30 mice. Co-exposure reduced albumin content and albumin/globulin ratio but increased significantly globulin content. Co administration showed strong correlation with cholesterol, urea, and HDL-C in both day 25 and 30 mice. Inverse correlation was found with alkaline phosphatase and albumin for day 25 and with triglycerides, globulin, and total protein content in day 30 Co-exposed mice. Subchronic CoCl2 exposure of immature mice induced significant changes in key metabolic parameters suggesting possible further disturbances in energy metabolism, osteogenesis, and reproduction. [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]

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]

Cobalt (Co) is widely used in many industrial fields such as batteries and paints. Cobalt, a dangerous heavy metal, can be found in high concentrations in natural and human habitats. Although cobalt is an important micronutrient, it is toxic to living organisms when exposed to high amounts. Carob (Ceratonia siliqua L.) is a tree native to The Mediterranean region. Carob bean, which has high nutritional and economic value, is used against cardiovascular and gastrointestinal diseases. In addition, the antioxidant properties of carob are gaining importance in recent years. In this study, the protective effects of carob extract against the toxicity of cobalt on Allium cepa L. were investigated. For this purpose, 150 mg/L and 300 mg/L carob extract solutions and 5.5 mg/kg cobalt solutions were applied to A. cepa L. bulbs. Root emergence, weight gain, root elongation, and mitotic index (MI) decreased, while the frequency of chromosomal abnormalities (CAs) and micronucleus (MN) increased as a result of Co application. Furthermore, Co treatment triggered a noticeable rise in the activities of superoxide dismutase (SOD) and catalase (CAT) enzymes as well as the malondialdehyde (MDA) amount and the abnormalities in the meristematic cells. On the other hand, applications of carob extracts mitigated cobalt-induced damages in a dose-dependent manner in all parameters. Therefore, the current study showed that the strong preventive potential of carob extract against phytotoxicity and genotoxicity is caused by Co in a model plant. The protective effects of carob extract on Co-induced toxicity were demonstrated for the first time in terms of reducing genotoxicity and oxidative stress response. [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]

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]

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]

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]

Although we did not measure patient blood Co ion levels until this investigation, we believe that assuming pre-operative blood Co ion levels were within normal limits will not influence the outcome. References 1 He H, Zhang Z (2022) Letter to the editor: Blood cobalt ion level in patients with different sizes of cobalt/chrome femoral head with the Accolade TMZF stem. [Extracted from the article]

With rapid development of the construction of nuclear power plants along the coast, the concern of negative effects of potentially unexpected release of nuclides on marine organisms has increased. Cobalt (Co) is one of the crucial nuclides in nuclear polluted seawater. The effect of its presence in seawater on life cycle of macroalgae has seldom been studied. In this investigation, a series of Co concentrations including 1, 10, 100 μg L−1, and 1, 10 mg L−1 (the background concentration of Co in culture seawater was determined to be at the level of 0.75 ± 0.11 μg L−1) were used to test the effects of their presence on spore germination, gametophyte growth and gametogenesis of the important brown macroalga Undaria pinnatifida. It was found that the spore germination rate of 10 mg L−1 group was significantly lower than that of the control group after 1- and 2 days exposure. The gametophyte sizes of 1 and 10 mg L−1 groups were much smaller than that of the control group after 6- and 12-days exposure. Oogonia and juvenile sporophytes were observed to appear in 1, 10 μg L−1 and the control groups after 12 and 15 days, respectively, but not in the higher concentration groups. In the recovery test, sporophytes appeared in the 100 μg L−1 group on the 5th day, but not in 1 and 10 mg L−1 groups. These results demonstrate that presence of Co at high concentrations in seawater disturbs the life cycle by suppressing both the gametophyte growth and gametogenesis in U. pinnatifida. [ABSTRACT FROM AUTHOR]

Exposure to circulating cobalt (Co2+) in patients with metal-on-metal orthopaedic hip implants has been linked to cardiotoxicity but the underlying mechanism(s) remain undefined. The aim of the current study was to examine the effects of Co2+ on the heart in vivo and specifically on cardiac fibroblasts in vitro. Adult male rats were treated with CoCl2 (1 mg/kg) for either 7 days or 28 days. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure Co2+ uptake into various organs of the body. Co2+ accumulated in the heart over time with significant levels evident after only 7 days of treatment. There was no evidence of cardiac remodelling following Co2+ treatment as assessed by heart weight:body weight and left ventricular weight:body weight. However, a decrease in fractional shortening, as measured using echocardiography, was observed after 28 days of Co2+ treatment. This was accompanied by increased protein expression of the ion transient receptor potential (TRP) channels TRPC6 and TRPM7 as assessed by quantitative immunoblotting of whole cardiac homogenates. Uptake of Co2+ specifically into rat cardiac fibroblasts was measured over 72 h and was shown to dramatically increase with increasing concentrations of applied CoCl2. Expression levels of TRPC6 and TRPM7 proteins were both significantly elevated in these cells following Co2+ treatment. In conclusion, Co2+ rapidly accumulates to significant levels in the heart causing compromised contractility in the absence of any overt cardiac remodelling. TRPC6 and TRPM7 expression levels are significantly altered in the heart following Co2+ treatment and this may contribute to the Co2+-induced cardiotoxicity observed over time. [ABSTRACT FROM AUTHOR]

Despite the increasing environmental threat of cobalt in the modern era, less is known as its phytotoxicity behavior. Therefore, the present study was undertaken to assess the toxicity effects of cobalt and to understand the associated physio-biochemical response in Brassica napus, an economically important plant crop species. Five-day-old seedlings of four cultivars (Zheda 619, Zheda 622, ZS 758, and ZY 50) were exposed to five different levels of cobalt under hydroponic conditions. Results showed a concentration-dependent inhibition of plant growth, accompanied by notable chlorophyll loss, protein degradation, and accumulation of reactive oxygen species and malondialdehyde. Further, Co contents in different plants parts were found to be higher in Zheda 622 than all other cultivars. In all cultivars, the contents of enzymatic activities (SOD, POD, GR, and GSH) were markedly increased following cobalt exposure; by contrast, catalase and ascorbate peroxidase activities declined with increased cobalt concentration in medium, which was also, echoed by the pattern of enzymes-related mRNA levels. Morphological observations, supported by ultrastructural analysis revealed clear differences in cobalt sensitivity among cultivars, with ZS 758 identified as less sensitive cultivar, and Zheda 622 the most sensitive one. In addition to revealing genotypic differences in cobalt sensitivity in B. napus, findings suggest the mechanisms of cobalt tolerance in this specie could, at least partially, in relation with the ability of plant to sustain the activity of superoxide dismutase and guaicol peroxidase and to maintain glutathione reduced pool through the action of glutathione reductase. [ABSTRACT FROM AUTHOR]

Over 300,000 hip replacements occurred in the USA in 2010, and the frequency is likely increasing annually. Blood Cobalt (Co) concentrations in patients with well-functioning cobalt-chromium (Co-Cr) hip implants are usually elevated above background concentrations relative to the general population. Excessive Co exposure, in rare cases, can result in cardiomyopathy. The purpose of this review was to identify cases of cardiomyopathy in metal-containing hip implant patients and to evaluate the possible cause of each patient’s cardiomyopathy. We evaluated 15 cases published between 2009 and 2016, and, based on a review of the preexisting risk factors, blood Co concentrations, and histopathological information published for each patient, they were stratified into one of four categories regarding the association between Co exposure and the development of cardiomyopathy: (1) Co was causal (five cases); (2) Co was contributory (two cases); (3) Co was possibly contributory (six cases); and (4) Co was non-causal (two cases). In all 15 cases, blood Co concentrations (14-6521 μg/L) were elevated beyond levels associated with the majority of metal-containing implant patients (0.1-10 μg/L), and, in many cases, there was evidence of a malfunctioning implant. The data indicate that individuals with well-functioning implants, even those with preexisting risk factors, are at no risk of developing cardiac effects. We conclude that blood Co measurements are informative, but should be interpreted with caution, and in context of other factors evaluated in this analysis. The mere presence of elevated Co is not sufficient to indicate causation for a patient’s cardiomyopathy. [ABSTRACT FROM AUTHOR]

Cobalt is a trace element that localizes in the human body as cobalamin, also known as vitamin B12. Excessive cobalt exposure induces a peripheral neuropathy, the mechanisms of which are yet to be elucidated. We investigated how cobalt may affect mitochondrial motility in primary cultures of rat dorsal root ganglion (DRG). We observed mitochondrial motility by time-lapse imaging after DsRed2 tagging via lentivirus, mitochondrial structure using transmission electron microscopy (TEM), and axonal swelling using immunocytochemical staining. The concentration of cobaltous ion (Co2+) required to significantly suppress mitochondrial motility is lower than that required to induce axonal swelling following a 24-h treatment. Exposure to relatively low concentrations of Co2+ for 48 h suppressed mitochondrial motility without leading to axonal swelling. TEM images indicated that Co2+ induces mitochondrial destruction. Our results show that destruction of the axonal mitochondria precedes the axonal degeneration induced by Co2+ exposure. [ABSTRACT FROM AUTHOR]

Purpose: Cobalt (Co) is a toxic metal to the environment and human’s health. The purpose of the study is to achieve an investigation into the efficacy of calcium carbonate and cow dung for Co immobilization in fluvo-aquic soil, as well as their effects on the antioxidant system in plants.Materials and methods: Calcium carbonate and cow dung were incorporated with the Co-polluted fluvo-aquic soil where pakchois (Brassica chinensis L.) were grown. Co concentration, superoxide dismutase (SOD) activity, catalase (CAT) activity, and malondialdehyde (MDA) concentration in the shoots of the mature plants were inspected.Results and discussion: As calcium carbonate concentration rose (0 to 12 g kg−1), Co concentration in shoots of the plants decreased firstly and then increased again (P < 0.05), while the accumulation level of Co kept decreasing with cow dung concentration rising (P < 0.05). Under the amendment treatments, the SOD activity, CAT activity, and MDA concentration in the shoots were all positively correlated to the Co concentration in the plant tissue (r = 0.792, 0.904, and 0.807, P < 0.01), indicating the antioxidant system receptivity to the Co accumulation. The amendments in soil can alleviate the oxidative stress in pakchois owing to Co pollution. As calcium carbonate concentration ranged from 5.64 to 7.86 g kg−1, the parameters reached a maxima (minimum), respectfully.Conclusions: Calcium carbonate and cow dung in fluvo-aquic soil are effective for Co immobilization and mitigating any pertinent oxidative stress in pakchoi plants. Calcium carbonate concentration within a range of 5.64 to 7.86 g·kg−1 will achieve optimum efficacy. [ABSTRACT FROM AUTHOR]

Compartmentalization of Co and Mn in Escherichia coli BL21 (D3) was investigated using Co and Mn as radioindicators. Living non-growing E. coli cells sequestered accumulated cobalt and manganese not only on cell surface but significant amounts of uptaken metals were associated with periplasmic space and cytoplasm. Both Co and Mn cell compartmentalization was time and concentration dependent process although total binding capacity of cells for Co was significantly lower compared to Mn. This should be considered in sorption studies especially in cases when metal recovery from bacterial cells is required or bacteria should be used in several sorption-desorption cycles. [ABSTRACT FROM AUTHOR]

Cobalt use is increasing particularly due to its use as one of the primary metals in cobalt-chromium-molybdenum (CoCrMo) metal-on-metal prosthetics. CoCrMo is a high-strength, wear-resistant alloy with reduced risk for prosthetic loosening and device fracture. More than 500,000 people receive hip implants each year in the USA which puts them at potential risk for exposure to metal ions and particles released by the prosthetic implants. Data show cobalt ions released from prosthetics reach the bloodstream and accumulate in the bladder. As patients with failed hip implants show increased urinary and blood cobalt levels, no studies have considered the effects of cobalt on human urothelial cells. Accordingly, we investigated the cytotoxic and genotoxic effects of particulate and soluble cobalt in urothelial cells. Exposure to both particulate and soluble cobalt resulted in a concentration-dependent increase in cytotoxicity, genotoxicity, and intracellular cobalt ions. Based on intracellular cobalt ion levels, we found, when compared to particulate cobalt, soluble cobalt was more cytotoxic, but induced similar levels of genotoxicity. Interestingly, at similar intracellular cobalt ion concentrations, soluble cobalt induced cell cycle arrest indicated by a lack of metaphases not observed after particulate cobalt treatment. These data indicate that cobalt compounds are cytotoxic and genotoxic to human urothelial cells and solubility may play a key role in cobalt-induced toxicity. [ABSTRACT FROM AUTHOR]

The toxicity of many heavy metals in plants is closely associated with its subcellular distribution and chemical forms. The subcellular distribution and chemical forms of cobalt (Co) were investigated using 3 barley genotypes differing in Co toxicity resistance, namely Yan66 (resistant), Ea 52 (sensitive), and Humai 4 (moderate), under two Co levels (25 and 100 µM). Higher Co level in cultural solution significantly increased Co accumulation in all subcellular fractions, with vacuole and cell wall having higher concentration. In comparison with 25 µM Co, 100 µM Co treatment caused significant increase of Co concentration in the forms of F-NaCl (extracted with 1 M NaCl), F-Ac (extracted with 2% HAc), F-HCl (extracted by 0.6 M HCl), and F-residue (residue forms) in both shoots and roots. There was a significant difference among genotypes in Co subcellular distribution and chemical forms, with Ea52 accumulating more Co in organelles and Yan66 accumulating more Co in vacuole and cell wall. Moreover, the inorganic form of Co extracted with 80% ethanol (F-ethanol) and water-soluble form (F-HO) were significantly increased in Ea52, while Yan66 accumulated more Co in the forms of low-bioavailable molecules (F-NaCl, F-HAc, and F-HCl). The results suggest that the vacuolar sequestration and cell wall deposition of Co is a key resistant mechanism for genotype Yan66. [ABSTRACT FROM AUTHOR]

Melamine functionalized cellulose@carbon nanotubes were prepared by the following method: (a) Cellulose was dissolved in a mixture of urea and NaOH solutions and then mixed with multiwall carbon nanotubes; (b) the MWCT-modified cellulose was precipitated by addition of water; (c) the MWCNTs were activated with thionyl chloride, and finally reacted with melamine. The resulting sorbent was used in preconcentration of Co(II) ions prior to their determination by flame atomic absorption spectroscopy. The sorbent was characterized by FTIR and field emission scanning electron microscopy. The effects of the pH value of the medium, contact time, and elution conditions were optimized. The calibration plot is linear in the 3 to 200 μg·L‾ Co(II) concentration range, the limit of detection is 0.8 μg·L‾, and the relative standard deviation (at a concentration of 100 μg·L‾) is 3.5 %. The maximum sorption capacity is 167 mg·g‾. The method was applied to the preconcentration of cobalt ions from (spiked) food and water samples and gave recoveries between 96 and 102 %. [ABSTRACT FROM AUTHOR]

Vitamin B (B) production is a strain specific, rare and hidden functional attribute of lactobacilli and a cogent protocol for selection of such isolates from the herd of lactobacilli is required. The present study included isolation of lactobacilli from human samples (milk and fecal), screening them by a polyphasic (three-phase) methodology for probable B production potential and validating the screening protocol by exploring selected strains for in vitro vitamin production (two-phase fermentation) and quantification [micro-assay and ultra fast liquid chromatography (UFLC)]. Fifty-nine Lactobacillus strains were recovered from tested biological samples. Contrary to screening inapplicabilities of first [growth potential (GP) in B-free medium] and second phases (GP in B-free and cobalt chloride-supplemented conditions), third phase (cbiK gene detection on genomic DNA) alone was revealed as a validated strategy for selection of two probable B-producing lactobacilli. Microbiological assay confirmed production and bioavailability of produced vitamin, while UFLC testing validated the results by precisely quantifying the cyanocobalamin (industrially produced bio-available form of B) in cell extracts of both possible B producers [BHM10 (10.91 ± 1.55 μg/l) and BCF20 (23.90 ± 1.73 μg/l)] and positive standard [ Lactobacillus reuteri DSM20016 (20.03 ± 4.17 μg/l)]. Moreover, this study generates a novel report for genomic detection, partial amplification and sequencing of cbiK gene in Lactobacillus plantarum species (both BHM10 and BCF20). In conclusion, contrary to first two phases, cbiK gene detection strategy successfully selects B-producing strains from a group of human-originated lactobacilli and can be used in the future for similar screening studies. [ABSTRACT FROM AUTHOR]

In this age of intensive industrialization and urbanization, mankind’s highest concern should be to analyze the effect of all metals accumulating in the environment, both those considered toxic and trace elements. With this aim in mind, a unique study was conducted to determine the potentially negative impact of Sn2+, Co2+, and Mo5+ in optimal and increased doses on soil biological properties. These metals were applied in the form of aqueous solutions of Sn2+ (SnCl2 · 2H2O), Co2+ (CoCl2 · 6H2O), and Mo5+ (MoCl5), each in the doses of 0, 25, 50, 100, 200, 400, and 800 mg kg−1 soil DM. The activity of dehydrogenases, urease, acid phosphatase, alkaline phosphatase, arylsulfatase, and catalase and the counts of twelve microorganism groups were determined on the 25th and 50th day of experiment duration. Moreover, to present the studied problem comprehensively, changes in the biochemical activity and yield of spring barley were shown using soil and plant resistance indices—RS. The study shows that Sn2+, Co2+, and Mo5+ disturb the state of soil homeostasis. Co2+ and Mo5+ proved the greatest soil biological activity inhibitors. The residence of these metals in soil, particularly Co2+, also generated a drastic decrease in the value of spring barley resistance. Only Sn2+ did not disrupt its yielding. The studied enzymes can be arranged as follows for their sensitivity to Sn2+, Co2+, Mo5+: Deh > Ure > Aryl > Pal > Pac > Cat. Dehydrogenases and urease may be reliable soil health indicators. [ABSTRACT FROM AUTHOR]

Cobalt is an essential heavy metal that is necessary for the formation of vitamin B12 (hydroxocobalamin). However, exposure to excess cobalt for a prolonged period can harm the human body, causing pulmonary fibrosis, blindness, deafness, and peripheral neuropathy. 3-Aminotriazole (3-AT) is a catalase inhibitor that is often used to investigate the physiological effects of catalase. The present study found that injection of 3-AT in mice significantly reduced CoCl-induced hearing impairment. In cultured organ of Corti explants from rats, 3-AT treatment protected hair cells from CoCl-induced cytotoxicity. To determine the mechanism by which 3-AT protected from CoCl-induced ototoxicity, we used the HEI-OC1 auditory cell line. Pretreatment with 10 mM 3-AT attenuated CoCl-induced accumulation of ROS and induction of proinflammatory cytokine expression. Interestingly, these protective effects of 3-AT did not require catalase activity, as demonstrated by a series of experiments using RNA interference-mediated catalase knockdown in HEI-OC1 cells and using catalase-deficient mouse embryonic fibroblasts. Our results demonstrated the mechanisms of CoCl-induced ototoxicity that may provide better ways to prevent the ototoxic effect of cobalt exposure. [ABSTRACT FROM AUTHOR]