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The excessive accumulation of cobalt (Co) in plant tissues severely impairs plant growth that ultimately reduces the yield. However, melatonin (MT) has been known to mediate the abiotic stress tolerance in plants. The present study aimed at investigating the protective mechanisms of exogenously applied MT (0, 50 and 100 μM) under Co (0, 100, 200 and 300 μM) stress by focusing on morpho-physiological, biochemical and cellular characterizations of Brassica napus plants. Cobalt (300 μM) alone treatment drastically inhibited the stomatal conductance, plant height (45%), leaf area (30%), free amino acid (139%), relative electrolyte leakage (109%), and total soluble sugars (71%), compared with the control. However, the exogenous supply of MT notably minimized the oxidative damage, lipid peroxidation and maintained the membrane integrity under Co-toxicity by restricting the overproduction of ROS (H2O2 and O2•), and MDA in leaves and roots. Melatonin significantly enhanced the activities of ROS-scavenging antioxidant enzymes, secondary metabolism-related phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), stress-responsive genes (heat shock protein as HSP-90, methyl transferase as MT) and regulated the Co-transporters, especially in roots. These findings indicated that an exogenous supply of MT improve the plant morphology, photosynthetic apparatus, osmotic adjustments, and antioxidant defense systems by enhancing the Co-detoxification in B. napus plants.

The purpose of this study was to investigate the sublethal Co toxicity on rainbow trout (Oncorhynchus mykiss). Trout were exposed to Co and selected parameters were evaluated at intervals of 1, 15 and 30 days. Fish exposed to higher levels of Co grew slower than fish exposed to lower levels of Co. Weight gain, specific growth rate (SGR) decreased linearly with the increase of cobalt in the water. The body condition factor (CF) of fish reared in water with low cobalt concentration decreased substantially but this decrease was not significant for fish exposed to higher cobalt concentration. The values of the feed conversion ratio (FCR) increased in fish exposed to higher levels of Co. Co significantly changed the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and decreased at day 30, and in both cases this decrease was more remarkable at day 15 so that the level of AST and ALT reached the control value at day 30. The alkaline phosphatase (ALP) level also showed a remarkable 15-day decline. There was a significant increase in glucose (G) concentration in both Co-exposed groups on day 15. However, serum cholesterol (Chl) was significantly reduced on day 15 and increased on day 30; there were no significant differences in both exposed Co-groups. The triglyceride (TG) level also decreased substantially. There was no regular pattern of total protein (TP) in the serum, so that no significant differences were found in the level of TP between low and high-exposed fish. In summary, this study suggests that exposure of essential trace elements such as cobalt may change growth and biochemical parameters, and that measurement of these parameters may be used in toxicological studies to determine the general health status of fish.

Prosthetic hip-associated cobalt toxicity (PHACT) is caused by elevated blood cobalt concentrations after hip arthroplasty. The aim of this study is to determine which symptoms are reported most frequently and in what type of bearing. We also try to determine the blood level of cobalt concentrations associated with toxicological symptoms. A systematic review was conducted on the 10th of July according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A methodological quality assessment (risk of bias (RoB)) was performed. Primary outcomes were the reported symptoms of cobalt toxicity and the level of cobalt concentrations in blood. These levels were associated with toxicological symptoms. A total of 7645 references were found of which 67 relevant reports describing 79 patients. The two most used bearings in which PHACT was described were metal-on-metal (MoM) bearings (38 cases) and revised (fractured) ceramic-on-ceramic (CoC) bearings where the former ceramic head was replaced by a metal head (32 cases). Of all reported symptoms, most were seen in the neurological system, of which 24% were in the sensory system and 19.3% were in central/peripheral system, followed by the cardiovascular (22.1%) system. The mean cobalt concentration for MoM-bearings was 123.7 ± 96.8 ppb and 1078.2 ± 1267.5 ppb for the revised fractured CoC-bearings. We recommend not to use a metal-based articulation in the revision of a fractured CoC bearing and suggest close follow-up with yearly blood cobalt concentration controls in patients with a MoM bearing or a revised fractured CoC bearing. Level of Evidence: Level V, systematic review.

Streptococcus suis is a zoonotic pathogen causing serious infections in swine and humans. Although metals are essential for life, excess amounts of metals are toxic to bacteria. Transcriptome-level data of the mechanisms for resistance to metal toxicity in S. suis are available for no metals other than zinc. Herein, we explored the transcriptome-level changes in S. suis in response to ferrous iron and cobalt toxicity by RNA sequencing. Many genes were differentially expressed in the presence of excess ferrous iron and cobalt. Most genes in response to cobalt toxicity showed the same expression trends as those in response to ferrous iron toxicity. qRT-PCR analysis of the selected genes confirmed the accuracy of RNA sequencing results. Bioinformatic analysis of the differentially expressed genes indicated that ferrous iron and cobalt have similar effects on the cellular processes of S. suis. Ferrous iron treatment resulted in down-regulation of several oxidative stress tolerance-related genes and up-regulation of the genes in an amino acid ABC transporter operon. Expression of several genes in the arginine deiminase system was down-regulated after ferrous iron and cobalt treatment. Collectively, our results suggested that S. suis alters the expression of multiple genes to respond to ferrous iron and cobalt toxicity.

Cobalt (Co) commonly co-exists with copper (Cu) in natural soils, but the information about their combined effects on plants is poorly available. In this study, we hydroponically investigated the combined effects of Co and Cu on two barley genotypes differing in Co toxicity tolerance to reveal the interaction pattern of these two metals. The results showed that single treatment of Co or Cu at the dose of 100 μM led to a significant decrease of growth and photosynthetic rate, and a significant increase of lipid peroxidation, ROS radicals as well as anti-oxidative enzyme (SOD, CAT and GR) activities and glutathione content, with the extent of effect being less in Yan66 than Ea52. The combined treatment of Co and Cu alleviated the toxicity of both metals in comparison with each metal treatment alone, as reflected by improved growth and photosynthesis, and much slight oxidative stress. The alleviation of metal toxicity upon combined treatment is mainly attributed to a drastic reduction of Co uptake and its translocation from roots to shoots. It may be suggested that interaction of Co and Cu on their uptake and movement in plants is antagonistic. • The interaction of Co and Cu is antagonistic. • The combined treatment of Cu and Co alleviated Co toxicity relative to Co treatment alone. • The alleviation of Co toxicity by combined treatment is attributed to the uptake and transportation of Co in plants. [ABSTRACT FROM AUTHOR]

This case illustrates the potential for systemic cobalt toxicity in non-metal-on-metal bearings and its potentially devastating consequences. We present a 71-year-old male with grinding sensations in his right hip following ceramic-on-ceramic total hip arthroplasty (THA). After diagnosing a fractured ceramic liner, the hip prosthesis was revised into a metal-on-polyethylene bearing. At one year postoperatively, X-rays and MARS-MRI showed a fixed reversed hybrid THA, with periarticular densities, flattening of the femoral head component, and a pattern of periarticular metal wear debris and pseudotumor formation. Before revision could take place, the patient was admitted with the clinical picture of systemic cobalt toxicity, supported by excessively high serum cobalt and chromium levels, and ultimately died. At autopsy dilated cardiomyopathy as cause of death was hypothesized. A third body wear reaction between ceramic remnants and the metal femoral head very likely led to excessive metal wear, which contributed systemic cobalt toxicity leading to neurotoxicity and heart failure. This case emphasizes that fractured ceramic-on-ceramic bearings should be revised to ceramic-on-ceramic or ceramic-on-polyethylene bearings, but not to metal-on-polyethylene bearings. We aim to increase awareness among orthopedic surgeons for clinical clues for systemic cobalt intoxication, even when there is no metal-on-metal bearing surface.

Copyright of Revista Española de Cirugía Ortopédica y Traumatologia (English Edition) is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Cobalt toxicity in patients with hip arthroplasty is a rare complication, but it should be considered in those patients who, after a ceramic fracture, were implanted with a metal-on-polyethylene prosthesis. The complete removal of ceramic particles during revision surgery can be complicated. If the bearing surface is replaced with a metal-on-polyethylene prosthesis, these residual ceramic particles may wear down the chrome-cobalt head, producing localised metallosis. This can trigger blood metal ion levels to rise, causing systemic toxicity. Visual and auditory alterations, cognitive deterioration, hypothyroidism, neuropathy, cardiomyopathy, anorexia, fatigue, diabetes, polycythemia, and respiratory and cutaneous symptoms are some of the clinical manifestations of prosthetic cobaltism. Case description: A young patient presented with multiorgan failure secondary to cobalt toxicity after a ceramic fracture and revision with a metal-on-polyethylene prosthesis; his serum cobalt and chromium levels were 652 μg/L and 270 μg/L, respectively. The patient needed a heart transplant after presenting with cobalt-induced cardiogenic shock. Conclusions: In a patient with a ceramic fracture who is subjected to revision surgery with a metal-on-polyethylene bearing, it is necessary to rule out the possibility of cobalt intoxication. Serum cobalt levels > 20 μg/L are inadmissible; in these cases, surgical treatment should be considered in the short term. A wide synovectomy and replacement of components should be performed with hard friction options, preferably with a ceramic-on-ceramic prosthesis. [ABSTRACT FROM AUTHOR]

Cobalt metallosis after revision metal-on-polyethylene total hip arthroplasty for catastrophic failure of ceramic components is uncommon but a potentially devastating complication. Common findings associated with heavy metal toxicity include cardiomyopathy, hypothyroidism, skin rashes, visual disturbances, hearing changes, polycythemia, weakness, fatigue, cognitive deterioration, and neuropathy. We report a case of a 57-year-old woman who presented with complaints of progressively worsening hip pain, fatigue, memory loss, lower extremity sensory loss, persistent tachycardia, and ocular changes 5 years after synovectomy and revision of a failed ceramic-on-ceramic total hip arthroplasty to metal-on-polyethylene components. A cobalt level of 788.1 ppb and chromium level of 140 ppb were found on presentation and subsequently decreased to 468.8 ppb and 105.9 ppb, respectively, 2 weeks after revision to a ceramic-on-polyethylene total hip arthroplasty. Improvement of symptoms accompanied this decrease in cobalt and chromium levels. Revision of failed ceramic arthroplasties with later-generation ceramics to avoid this potential complication is recommended.

Nanoparticle-based magnetic hyperthermia is a well-known thermal therapy platform studied to treat solid tumors, but its use for monotherapy is limited due to incomplete tumor eradication at hyperthermia temperature (45 °C). It is often combined with chemotherapy for obtaining a more effective therapeutic outcome. Cubic-shaped cobalt ferrite nanoparticles (Co-Fe NCs) serve as magnetic hyperthermia agents and as a cytotoxic agent due to the known cobalt ion toxicity, allowing the achievement of both heat and cytotoxic effects from a single platform. In addition to this advantage, Co-Fe NCs have the unique ability to form growing chains under an alternating magnetic field (AMF). This unique chain formation, along with the mild hyperthermia and intrinsic cobalt toxicity, leads to complete tumor regression and improved overall survival in an in vivo murine xenograft model, all under clinically approved AMF conditions. Numerical calculations identify magnetic anisotropy as the main Co-Fe NCs' feature to generate such chain formations. This novel combination therapy can improve the effects of magnetic hyperthermia, inaugurating investigation of mechanical behaviors of nanoparticles under AMF, as a new avenue for cancer therapy., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Cobalt (Co) contamination in soils is becoming a severe issue in environment safety and crop production. Calcium (Ca) , as a macro-nutrient element, shows the antagonism with many divalent heavy metals and the capacity of alleviating oxidative stress in plants. In this study, the protective role of Ca in alleviating Co stress was hydroponically investigated using two barley genotypes differing in Co toxicity tolerance. Barley seedlings exposed to 100 µM Co showed the significant reduction in growth and photosynthetic rate, and the dramatic increase in the contents of reactive oxygen species (ROS), malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG), and the activities of anti-oxidative enzymes, with Ea52 (Co-sensitive) being much more affected than Yan66 (Co-tolerant). Addition of Ca in growth medium alleviated Co toxicity by reducing Co uptake and enhancing the antioxidant capacity. The effect of Ca in alleviating Co toxicity was much greater in Yan66 than in Ea52. The results indicate that the alleviation of Co toxicity in barley plants by Ca is attributed to the reduced Co uptake and enhanced antioxidant capacity. [ABSTRACT FROM AUTHOR]

Streptococcus suis is a zoonotic pathogen causing serious infections in swine and humans. Although metals are essential for life, excess amounts of metals are toxic to bacteria. Transcriptome-level data of the mechanisms for resistance to metal toxicity in S. suis are available for no metals other than zinc. Herein, we explored the transcriptome-level changes in S. suis in response to ferrous iron and cobalt toxicity by RNA sequencing. Many genes were differentially expressed in the presence of excess ferrous iron and cobalt. Most genes in response to cobalt toxicity showed the same expression trends as those in response to ferrous iron toxicity. qRT-PCR analysis of the selected genes confirmed the accuracy of RNA sequencing results. Bioinformatic analysis of the differentially expressed genes indicated that ferrous iron and cobalt have similar effects on the cellular processes of S. suis . Ferrous iron treatment resulted in down-regulation of several oxidative stress tolerance-related genes and up-regulation of the genes in an amino acid ABC transporter operon. Expression of several genes in the arginine deiminase system was down-regulated after ferrous iron and cobalt treatment. Collectively, our results suggested that S. suis alters the expression of multiple genes to respond to ferrous iron and cobalt toxicity.

Background: Cobalt is an important metal cofactor of many living cells. However, excessive cobalt is toxic and can cause cell death and even several diseases in humans. Saccharomyces cerevisiae is a useful tool for studying metal homeostasis and many of the genes and pathways are highly conserved in higher eukaryotes including humans., Methods: The intracellular cobalt and reactive oxygen species (ROS) levels were measured by an atomic absorption spectrometer and DHE staining method, respectively. The expression of genes involved in scavenging oxidative stress was tested by qPCR method, while the expression of UPRE-lacZ report gene was analyzed via β-galactosidase activity assay., Results: Using a genome-scale genetic screen, 153 cobalt-sensitive and 37 cobalt-tolerant gene deletion mutants were identified from Saccharomyces cerevisiae. We showed that 101 of the cobalt-sensitive mutants accumulated higher intracellular cobalt compared to wild-type. The intracellular ROS levels in 112 of the mutants were induced by cobalt, which might be caused by the decreased expression of genes involved in scavenging oxidative stress in response to cobalt. Moreover, more than one-third of the cobalt-sensitive mutants were also sensitive to tunicamycin, and cobalt stress might induce the unfolded protein response (UPR) through serine/threonine kinase and endoribonuclease Ire1., Conclusions: This study reinforced the fact that cobalt toxicity might be due to the high intracellular cobalt and ROS levels, and the endoplasmic reticulum stress responses induced by cobalt., General Significance: Elucidating the toxicity mechanisms of cobalt stress response will help reveal new routes for the treatment of the diseases induced by cobalt., (Copyright © 2020. Published by Elsevier B.V.)

Adverse local tissue reactions secondary to mechanically assisted crevice corrosion (MACC) at the trunnion is a complication of total hip arthroplasty known to cause local soft-tissue damage. However, what is not as well appreciated is that MACC in metal-on-polyethylene (MOP) articulations can lead to cobalt ion serum elevations with associated neurological dysfunction just as in metal-on-metal articulations. We report a compelling case for the association of neurologic dysfunction tied to metal ion elevations secondary to MACC at two distinct MOP tapers in a 58-year-old intensive care unit nurse with two hips implanted 3 years apart. This report further raises awareness about the potential of MACC-generated elevated ion levels to produce neurological symptoms that might otherwise be overlooked in patients with MOP articulations.

This case illustrates the potential for systemic cobalt toxicity in non-metal-on-metal bearings and its potentially devastating consequences. We present a 71-year-old male with grinding sensations in his right hip following ceramic-on-ceramic total hip arthroplasty (THA). After diagnosing a fractured ceramic liner, the hip prosthesis was revised into a metal-on-polyethylene bearing. At one year postoperatively, X-rays and MARS-MRI showed a fixed reversed hybrid THA, with periarticular densities, flattening of the femoral head component, and a pattern of periarticular metal wear debris and pseudotumor formation. Before revision could take place, the patient was admitted with the clinical picture of systemic cobalt toxicity, supported by excessively high serum cobalt and chromium levels, and ultimately died. At autopsy dilated cardiomyopathy as cause of death was hypothesized. A third body wear reaction between ceramic remnants and the metal femoral head very likely led to excessive metal wear, which contributed systemic cobalt toxicity leading to neurotoxicity and heart failure. This case emphasizes that fractured ceramic-on-ceramic bearings should be revised to ceramic-on-ceramic or ceramic-on-polyethylene bearings, but not to metal-on-polyethylene bearings. We aim to increase awareness among orthopedic surgeons for clinical clues for systemic cobalt intoxication, even when there is no metal-on-metal bearing surface. [ABSTRACT FROM AUTHOR]

Context:Post-arthroplasty metallosis, which refers to metallic corrosion and deposition of metallic debris in the periprosthetic soft tissues of the body, is an uncommon complication. Systemic cobalt toxicity post-arthroplasty is extremely rare. The few known fatal cases of cobalt toxicity appear to be a result of replacing shattered ceramic heads with metal-on-metal or metal-on-polyethylene implants. Friction between residual shards of ceramic and cobalt–chromium implants allows release of cobalt into the synovial fluid and bloodstream, resulting in elevated whole blood cobalt levels and potential toxicity. Case details:This is a single patient chart review of a 60-year-old woman with prior ceramic-on-ceramic right total hip arthroplasty complicated by fractured ceramic components and metallosis of the joint. She underwent synovectomy and revision to a metal-on-polyethylene articulation. Ten months post-revision, she presented to the emergency department (ED) with right hip pain, dyspnea, worsening hearing loss, metallic dysgeusia, and weight loss. Chest CTA revealed bilateral pulmonary emboli (PE), and echocardiogram revealed new cardiomyopathy with global left ventricular hypokinesis with an ejection fraction (EF) of 35–40% inconsistent with heart strain from PE. Whole blood cobalt level obtained two days into her admission was 424.3 mcg/L and 24-h urine cobalt level was 4830.5 mcg/L. Although the patient initially clinically improved with regard to her PE and was discharged to home on hospital day 5, she returned 10 days later with a right hip dislocation and underwent closed reduction of the hip. The patient subsequently decompensated, developing cardiogenic shock, and respiratory failure. She went into pulseless electrical activity (PEA) and expired. Autopsy revealed an extensive metallic effusion surrounding the right hip prosthesis that tested positive for cobalt (41,000 mcg/L). There was also cobalt in the heart muscle tissue (2.5 mcg/g). A whole blood cobalt level obtained two days before she expired was 641.6 mcg/L. Discussion:This is a case of fatal cobalt-induced cardiomyopathy in a patient whose ceramic components of a total hip arthroplasty fractured causing metallosis with worsening cobalt toxicity. We recommend that when a fractured device is revised with a prosthesis with cobalt–chromium components, whole blood and urine cobalt measurements should be obtained and periodically monitored to evaluate for rising concentrations. Providers should be aware of clinical signs and symptoms of cobalt toxicity in patients who have prostheses with cobalt–chromium components. If suspected, toxicology and orthopedics should be involved for possible chelation and removal of the prosthesis. [ABSTRACT FROM PUBLISHER]

Metal toxicity from metal-on-metal hip replacements is now well documented and several large series have reported local reactions. Although less common, there are reports of similar reactions from failed ceramic liners. Systemic effects documented in literature have been grouped into cardiac, neuro-ocular and thyroid signs.~Introduction~Background~We report a case of a patient who had revision for fractured ceramic liner to metal on polyethylene. Third body effect of the ceramic particles led to wear through of the poly liner and the head directly articulating with metal shell. He developed cardiac and neurological features of cobalt toxicity in addition to extensive soft tissue destruction. Revision of the bearing surfaces and synovectomy led to clinical improvement and fall in metal ion levels.~Methods and Results~Results~We recommend 2-stage revision in such situations and close monitoring of all these patients.~Conclusions~Conclusions [ABSTRACT FROM AUTHOR]

Background: Prosthetic hip-associated cobalt toxicity (PHACT) is an uncommon, but potentially devastating, complication for patients with metal-on-metal hip implants (MoMs). Clinical management of PHACT is poorly defined, with primary intervention being MoM explant followed by chelation therapy. Therapeutic plasma exchange (TPE) in cobalt toxicity has not been previously described. Given that cobalt is predominantly albumin bound, it should theoretically be removed by TPE. Here we report a case of PHACT and our experience using TPE to lower plasma cobalt levels., Case Report: A 61-year-old woman developed deafness, blindness, ambulatory dysfunction, and endocrinopathies after MoM implant. Cobalt levels on admission were greater than 1500 µg/L. In an attempt to rapidly lower cobalt levels before MoM explant, hemodialysis and TPE were performed. Hemodialysis removed negligible amounts of cobalt. One session of TPE temporarily removed approximately two-thirds of measurable cobalt, but levels rebounded to pre-TPE values after 8 hours. It was only after MoM removal that cobalt levels plateaued below 300 µg/L and clinical symptoms improved., Discussion: TPE removed cobalt from a PHACT patient, but a durable decrease in cobalt was only achieved after MoM explant. These findings are comparable to reports where chelation was employed in PHACT patients before MoM explant. The observed rebound phenomenon is likely from rapid equilibration between the immense extravascular tissue source (the MoM) and the intravascular compartment., Conclusion: TPE may serve as adjunctive therapy for PHACT patients whose cobalt levels remain high after explant, especially in patients with renal failure, in whom chelation is contraindicated., (© 2016 AABB.)

Uptake and toxicity of Ni-Co mixtures in Enchytraeus crypticus were determined after 4 d, 7 d, 10 d, and 14 d exposure. Generally, body concentrations of Ni and Co increased with increasing exposure concentrations. Ni body concentration was significantly reduced in the presence of Co, whereas Ni only marginally affected Co uptake. When expressed as free ion activities, individual toxicity of Ni and Co increased with time, with median lethal concentrations (LC50) decreasing from 78.3 μM and 511 μM at 4 d to 40.4 μM and 393 μM at 14 d, respectively. When expressed as body concentrations, LC50BodyNi remained constant with time whereas LC50BodyCo increased during the first 7 d but remained stable afterwards. As identified by the MIXTOX model, interactions between Ni and Co were mainly antagonistic when based on free ion activities, however, no interaction was observed when based on body concentrations. A process-based model, incorporating exposure time to analyze the mechanisms underlying the dynamic mixture toxicity confirmed the differences in toxicokinetics of the 2 metals. The author's findings suggest that body concentrations, which incorporate bioaccumulation processes, are time-independent and can act as a more constant indicator of metal toxicity. The observed antagonism was mainly caused by competition between Co and Ni for binding sites and subsequent inhibition of Ni uptake. This competitive interaction occurred at the uptake level (toxicokinetics), but not at the target level (toxicodynamics)., (© 2014 SETAC.)

Adverse local tissue reactions secondary to mechanically assisted crevice corrosion (MACC) at the trunnion is a complication of total hip arthroplasty known to cause local soft-tissue damage. However, what is not as well appreciated is that MACC in metal-on-polyethylene (MOP) articulations can lead to cobalt ion serum elevations with associated neurological dysfunction just as in metal-on-metal articulations. We report a compelling case for the association of neurologic dysfunction tied to metal ion elevations secondary to MACC at two distinct MOP tapers in a 58-year-old intensive care unit nurse with two hips implanted 3 years apart. This report further raises awareness about the potential of MACC-generated elevated ion levels to produce neurological symptoms that might otherwise be overlooked in patients with MOP articulations.

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction and objective: Prosthetic hip-associated cobalt toxicity (PHACT) is a rare cause of cobalt toxicity from metal-on metal (MoM) total hip prosthesis. There are few reports of PHACT and only one case report from our review that reported tremor as a presenting symptom (7). Case presentation: This is a report of a 44 year old male with history of hip replacement. He presented to PCP with progressive worsening of muscle weakness, fatigue and tremor of two months duration. After an extensive work up was performed and reviewing current literature, serum cobalt level was eventually performed and was found to be high. Resolution of the symptoms with concomitant decrease in serum cobalt was noted. Discussion: PHACT being a diagnosis which is rare and done by exclusion, it is important to make it a part of the differential diagnosis. As our patient also has the diagnosis of Charcot Marie Tooth, it is important to prevent anchoring heuristic bias and evaluate the patient from fresh eyes especially with a history of MoM device placement. Conclusion: The symptoms did resolve on removing the MoM device which does imply that PHACT can be regarded closer to a fact when compared to a fiction.

A fifty-two-year-old man underwent heart transplantation at our centre after four years of developing progressive heart failure symptoms due to cobalt toxicity-related cardiomyopathy. Between the ages of forty and forty-two, he underwent bilateral metal-on-metal hip arthroplasties for early onset osteoarthritis. Six years later, he developed increasing fatigue and pericardial effusions. Following a prolonged period of deterioration without a clear cause, the diagnosis of cobalt toxicity-related cardiomyopathy due to cobalt-chromium alloy hip prostheses was eventually made. He underwent bilateral revision hip arthroplasties and was listed for heart transplantation. Metal-on-metal joint replacement is a rare cause of iatrogenic cobalt toxicity. Anaesthetists may encounter patients with unexplained symptoms of heart failure, having a high index of suspicion presenting an opportunity for early diagnosis and intervention before end-stage disease develops. [ABSTRACT FROM AUTHOR]

Systemic poisoning related to cobalt–chromium total hip arthroplasty can affect multiple organs. In the otolaryngologic area the most frequent symptoms are tinnitus and hearing loss. In this report, we describe 2 patients with cobalt-containing hip prostheses who presented with otologic symptoms. The first case describes a patient with an extremely high cobalt blood level, which we believe may be one of the highest reported to date, after replacing a broken ceramic-on-ceramic prosthesis with a metal-on-metal prosthesis. This patient suffered all known complications associated with cobalt poisoning and survived. The second case, a female patient with a left resurfacing metal-on-metal prothesis, presented with bilateral continuous high-pitched tinnitus that started 8 months after surgery. Orthopedic surgeons and otologists should be vigilant for cobalt-induced ototoxicity in patients with metal-on-metal total hip prostheses. [ABSTRACT FROM AUTHOR]