Evaluation of the carcinogenic risks to humans associated with surgical implants and other foreign bodies - a report of an IARC Monographs Programme Meeting. International Agency for Research on Cancer

Comprehensive review on toxic heavy metals in the aquatic system: sources, identification, treatment strategies, and health risk assessment

Heavy metal pollution in water sources has become a major worldwide environmental issue, posing a threat to aquatic ecosystems and human health. The pollution of the aquatic environment is increasing as a result of industrialization, climate change, and urban development. The sources of heavy metal pollution in water include mining waste, leachates from landfills, municipal and industrial wastewater, urban runoff, and natural events such as volcanism, weathering, and rock abrasion. Heavy metal ions are toxic and potentially carcinogenic. They can also buildup in biological systems and cause bioaccumulation even at low levels of exposure, heavy metals can cause harm to organs such as the nervous system, liver and lungs, kidneys and stomach, skin, and reproductive systems. There were various approaches tried to purify water and maintain water quality. The main purpose of this article was to investigate the occurrence and fate of the dangerous contaminants (Heavy metal and metalloids) found in domestic and industrial effluents. This effluent mixes with other water streams and is used for agricultural activities and other domestic activities further complicating the issue. It also discussed conventional and non-conventional treatment methods for heavy metals from aquatic environments. Conclusively, a pollution assessment of heavy metals and a human health risk assessment of heavy metals in water resources have been explained. In addition, there have been efforts to focus on heavy metal sequestration from industrial waste streams and to create a scientific framework for reducing heavy metal discharges into the aquatic environment.

Awareness and preparedness level of medical workers for radiation and nuclear emergency response

Radiological science and nuclear technology have made great strides in the twenty-first century, with wide-ranging applications in various fields, including energy, medicine, and industry. However, those developments have been accompanied by the inherent risks of exposure to nuclear radiation, which is a source of concern owing to its potentially adverse effects on human health and safety and which is of particular relevance to medical personnel who may be exposed to certain cancers associated with low-dose radiation in their working environment. While medical radiation workers have seen a decrease in their occupational exposure since the 1950s thanks to improved measures for radiation protection, a concerning lack of understanding and awareness persists among medical professionals regarding these potential hazards and the required safety precautions. This issue is further compounded by insufficient capabilities in emergency response. This highlights the urgent need to strengthen radiation safety education and training to ensure the well-being of medical staff who play a critical role in radiological and nuclear emergencies. This review examines the health hazards of nuclear radiation to healthcare workers and the awareness and willingness and education of healthcare workers on radiation protection, calling for improved training programs and emergency response skills to mitigate the risks of radiation exposure in the occupational environment, providing a catalyst for future enhancement of radiation safety protocols and fostering of a culture of safety in the medical community.

Development of Ti-10Nb alloy by powder metallurgy processing route for dental application

Titanium and its alloys are used to make dental implants because of its low density, high strength, and corrosion resistance. This paper describes the development of a potential biomaterial Ti-10Nb by powder metallurgy utilizing four different compaction pressures and analyses its microstructural, physical, mechanical, electrochemical, biological, and tribological behavior under various situations. The alloys were fabricated using four different compaction pressures, that is, 600, 650, 700, and 750 MPa, and sintered in a vacuum atmosphere at 1000°C for 1.5 h. The density of the samples was measured using Archimedes principle. X-ray diffraction and scanning electron microscopy equipped with energy dispersive spectroscopy were used to investigate the phase composition and microstructure, and a profilometer was used to examine the surface roughness of various samples. Vickers hardness tester was used to evaluate hardness, and a universal testing machine was used for compression testing. Corrosion and wear behavior were examined using a potentiostat and a Bio-Tribometer, respectively. This Ti-10Nb alloys consist of α + β phase, and have 16% highest porosity in sample compacted at 600 MPa. The samples compacted at 750 MPa achieved highest hardness, yield strength, compressive strength, and elastic modulus of 450 ± 29.72 HV, 718.22 ± 16.37 MPa, 1543.59 ± 24.37 MPa, and 41.27 ± 3.29 GPa, respectively. In addition, it also possesses highest corrosion and wear resistance with lowest icorr of 0.3954 ± 0.008 μA/cm2 and wear volume of (31.25 ± 0.206) × 10-3  mm3 . These results indicate that the developed alloys have a variety of desirable properties, including high hardness, adequate compressive strength, good corrosion and wear resistance, apatite-forming capability, and a low elastic modulus, which is advantageous for avoiding stress shielding. Therefore, it may be recommended to use it as a dental implant material.

Bladder cancer risk in relation to occupations held in a nationwide case-control study in Iran

Globally, bladder cancer has been identified as one of the most frequent occupational cancers, but our understanding of occupational bladder cancer risk in Iran is less advanced. This study aimed to assess the risk of bladder cancer in relation to occupation in Iran. We used the IROPICAN case-control study data including 717 incident cases and 3477 controls. We assessed the risk of bladder cancer in relation to ever working in major groups of the International Standard Classification of Occupations (ISCO-68) while controlling for cigarette smoking, opium consumption. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI). In men, decreased ORs for bladder cancer were observed in administrative and managerial workers (OR 0.4; CI: 0.2, 0.9), and clerks (OR 0.6; CI: 0.4, 0.9). Elevated ORs were observed in metal processors (OR 5.4; CI: 1.3, 23.4), and workers in occupations with likely exposure to aromatic amines (OR 2.2; CI: 1.2, 4.0). There was no evidence of interactions between working in aromatic amines-exposed occupations and tobacco smoking or opium use. Elevated risk of bladder cancer in men in metal processors and workers likely exposed to aromatic amines aligns with associations observed outside Iran. Other previously confirmed associations between high-risk occupations and bladder cancer were not observed, possibly due to small numbers or lack of details on exposure. Future epidemiological studies in Iran would benefit from the development of exposure assessment tools such as job exposure matrices, generally applicable for retrospective exposure assessment in epidemiological studies.

Synthesis of a quinoxaline-hydrazinobenzothiazole based probe-single point detection of Cu2+, Co2+, Ni2+ and Hg2+ ions in real water samples

A novel quinoxaline-hydrazinobenzothiazole based sensor was synthesized and characterized using NMR, FTIR, and Mass spectroscopy techniques. The sensor achieves the distinct "single-point" colorimetric and fluorescent detection of Cu²⁺, Co²⁺, Ni²⁺ and Hg²⁺ ions with distinguishable color changes from yellow to red, pale red, pale brown and orange, respectively. The UV-visible and fluorescence emission spectral investigation revealed the excellent single-point sensing ability of the probe towards four different heavy metal ions with a ratiometric response. Nanomolar levels of detection of about 1.16 × 10^-7 M, 9.92 × 10^-8 M, 8.21 × 10^-8 M, and 1.14 × 10^-7 M for Cu²⁺, Co²⁺, Ni²⁺ and Hg²⁺ ions, respectively, were achieved using our sensor, which are below the US-EPA permissible limits. Additionally, the sensor was utilized for naked eye detection under normal daylight. Quantitative determination of the metal ions in real water samples was also demonstrated.

Optimization of the effect of microelectrodes on Ni2+ removal in three-dimensional electrode system

This study investigated Ni⁺² removal performance in 3DER reactors where electrocoagulation mechanisms and microelectrodes are used together. EDTA modification was carried out on the granule-activated carbon surface to increase the efficiency and affinity of microelectrodes against Ni⁺² molecules. The grafting was examined using BET, FT-IR, SEM, EDS, and the elemental mapping methods. With the surface analyses made in this study, it was revealed that EDTA modification on granulated activated carbon was successfully performed. Also, 8.48%wt by mass of EDTA grafting on granular activated carbon was possible. EDTA functionalization did not affect the surface pore structures of CAC much. Under 10 V potential, 97.82% Ni removal efficiency was obtained with 2D in 35 min, while 96.69% removal in 10 min and 100% removal in 15 min were obtained in the 3D reactor. The Ni⁺² removal mechanism in 3DER reactors has been determined to conform to the pseudo-second-order kinetic model. The k₂ value obtained for 10 V (1.36 10^-2) is 27 times the k₂ value obtained for 5 V for 3DER reactors. In addition, using central composite design (CCD), operational parameters such as time, concentration, and potential difference affecting Ni⁺² removal in 3DER reactors have been optimized. The most influential parameter is the applied voltage, followed by time and concentration. It has been determined that 3DER reactors using EDTA-modified microelectrodes are highly efficient and suitable for Ni⁺² removal.

Perspectives of nanomaterials in microbial remediation of heavy metals and their environmental consequences: A review

Nanomaterials (NMs) have diverse applications in various sectors, such as decontaminating heavy metals from drinking water, wastewater, and soil. Their degradation efficiency can be enhanced through the application of microbes. As microbial strain releases enzymes, which leads to the degradation of HMs. Therefore, nanotechnology and microbial-assisted remediation-based methods help us develop a remediation process with practical utility, speed, and less environmental toxicity. This review focuses on the success achieved for the bioremediation of heavy metals by nanoparticles and microbial strains and in their integrated approach. Still, the use of NMs and heavy metals (HMs) can negatively affect the health of living organisms. This review describes various aspects of the bioremediation of heavy materials using microbial nanotechnology. Their safe and specific use supported by bio-based technology paves the way for their better remediation. We discuss the utility of nanomaterials for removing heavy metals from wastewater, toxicity studies and issues to the environment with their practical implications. Nanomaterial assisted heavy metal degradation coupled with microbial technology and disposal issues are described along with detection methods. Environmental impact of nanomaterials is also discussed based on the recent work conducted by the researchers. Therefore, this review opens new avenues for future research with an impact on the environment and toxicity issues. Also, applying new biotechnological tools will help us develop better heavy metal degradation routes.

Potentially toxic elements exposure biomonitoring in the elderly around the largest polymetallic rare earth ore mining and smelting area in China

Potentially toxic elements (PTEs) can be released during mining operations and ore processing. The pollution and health risk related to PTEs in total suspended particulates (TSPs) around the largest polymetallic rare earth mining area (Bayan Obo) and smelting area (Baotou) in Inner Mongolia, China, were evaluated. PTEs in the hair of the elderly living in these two areas and a reference area (Hohhot) were also examined. Relationships between PTEs in TSPs and hair with categorical factors (location, gender, etc.) were also modeled. Multivariate statistical analyses were carried out to analyze the possible sources of the PTEs in TSPs. The bubble maps of the concentrations of PTEs indicated that high concentrations of PTEs were near the industrial area where smelting plants and power plants were located. In addition, health risks were assessed for adults in the mining and smelting area. The carcinogenic risk of Cr was high for residents in the study areas. Also, the residents were exposed to a non-carcinogenic risk of Ni. Significant mean value differences were observed between PTEs in the hair of the elderly in Baotou and Hohhot. Results of the linear regression model indicated that around 31 % of the Pb in hair could be explained by the linear regression model, it could be affected by Ni and Zn in TSPs, but location, gender, and sampling time showed no significant contribution. Age was not significantly associated with the PTEs levels in hair in Baotou and Bayan Obo. The results provide important scientific evidence for a better understanding of the effects of PTEs in TSPs in polymetallic ore mining and smelting areas.

Air Quality Assessment by the Determination of Trace Elements in Lichens (Xanthoria calcicola) in an Industrial Area (Sicily, Italy)

This study provides data on variation in the content of metals and metalloids measured in the lichens (Xanthoria calcicola Oxner) collected in the Syracusan petrochemical complex (Sicily, Italy) which is considered one of the largest in Europe. Concentrations of eighteen trace elements measured in the lichens that were collected from 49 different points were analyzed using an inductively coupled plasma (ICP-MS) device. The concentrations of the typical elements of industrial emissions (As, Cr, Ni, and V) highlight the environmental criticality that exists in the study area. The interpretation of the data in terms of multi-element statistical analysis (FA) and enrichment factor (EFs) proved to be particularly useful in identifying several sources that contribute to the presence of trace elements in the atmospheric particulate between anthropogenic emissions and geogenic emissions. The results of this study reveal the versatility of the lichen species Xanthoria calcicola Oxner in the search for trace elements in highly anthropized environments, so the approach followed in this study can also be applied to other industrial contexts.

Microstructure and load bearing capacity of TiN/NbN superlattice coatings deposited on medical grade CoCrMo alloy by HIPIMS

In recent years significant progress has been made in the application of various ceramic, namely Metal nitride (MeN) functional coatings to engineer the surfaces of medical implants utilising metal-on-metal (MoM) articulation. This article reports on the load bearing capacity and structural response of TiN/NbN superlattice coatings deposited on medical grade CoCrMo alloy substrate under the application of localised load and the subsequent crack formation mechanism. The coatings have been deposited by mixed High Power Impulse Magnetron Sputtering-Unbalanced Magnetron Sputtering (HIPIMS-UBM) process. In the case of TiN/NbN coating deposited on CoCrMo substrate where Ecoating/Esubstrate is as high as 1.81 indicating that the substrate does not provide the necessary load bearing support for the brittle thin film, the utilisation of the Berkovich indentation technique proved to be a potent approach to study coating material as well as structural response to applied concentrated load. FIB/SEM analyses of the indented coatings revealed that in the hard-on-soft material systems cracks will initiate due to sub-coating substrate deformation and then propagate towards the coating surface. The FIB/SEM and low magnification XTEM analysis showed that an exceptionally strong TiN/NbN coating substrate adhesion bonding was achieved due to the utilisation of the HIPIMS pre-treatment. High resolution XTEM analyses revealed, for the first time, that during the indentation a collective rotation and alignment of the individual layers of the superlattice stack takes place without compromising coatings integrity which is clear evidence for the exeptionally high coating fracture toughness. The high toughness of the superlattice structured TiN/NbN coatings combined with their exceptionally high adhesion on madical grade CoCrMo ranks them as a strong candidate for medical implant applications.

Investigation of nickel sulfate-induced cytotoxicity and underlying toxicological mechanisms in human umbilical vein endothelial cells through oxidative stress, inflammation, apoptosis, and MAPK signaling pathways

Growing evidence indicates that nickle and its compounds have adverse effects on the cardiovascular system. In this study, the cytotoxic insults caused by nickel sulfate (NiSO₄ ) in human umbilical vein endothelial cells (HUVECs) were explored by examining cell viability, oxidative stress, inflammation, apoptosis, and MAPK signaling pathway activity. Cultured HUVECs were treated with varying concentrations of NiSO₄ (0, 62.5, 250, and 1000 μM) for 24 h. Subsequently, markers of oxidative stress, inflammation, apoptosis, and MAPK signaling pathways were analyzed using biochemical assays, real-time quantitative polymerase chain reaction, and western blot. Rates of apoptosis were evaluated using flow cytometry. The results showed that NiSO₄ exerted dose- and time-dependent inhibitory effects on cell growth. It induced oxidative stress and lipid peroxidation by increasing the generation of reactive oxygen species, the oxidized glutathione to reduced glutathione ratio (GSSG/GSH ratio), and malondialdehyde levels. Further, it inhibited superoxide dismutase activity in HUVECs. Flow cytometry analysis results revealed that NiSO₄ (62.5-1000 μM) could induce apoptosis in HUVECs. The protein and gene expressions of cleaved Caspase 3 and Bax were elevated, and those of Bcl-2 and Bcl-XL were reduced after NiSO₄ treatment. Additionally, NiSO₄ triggered inflammation in HUVECs, increasing the protein and mRNA levels of IL-6 and TNF-α and reducing those of TGF-β. Furthermore, western blot findings revealed that NiSO₄ could activate MAPK signaling pathways, upregulating p38, JNK, and ERK1/2 in HUVECs by increasing the levels of p-P38，p-JNK, and p-ERK1/2 in a dose-dependent manner. MAPK pathway inhibitors (10 μM SB203580 and 10 μM SP600125) could attenuate the NiSO₄ -induced increase in apoptosis and inflammation in HUVECs. They could also attenuate the dysregulation of inflammatory factors and related proteins caused by high-dose NiSO₄ exposure. Interestingly, while the MEK inhibitor U0126 (10 μM) enhanced NiSO₄ -induced apoptosis in HUVECs, it reduced cell inflammation. Taken together, these experimental results suggest that NiSO₄ can inhibit cell growth, induce oxidative stress, and trigger subsequent inflammatory responses and apoptosis in HUVECs. These effects may be mediated by the P38 and JNK MAPK stress response pathways.

Serum trace element levels of gastrointestinal cancer patients in an endemic upper gastrointestinal cancer region

Gastrointestinal (GI) cancers are an important cause of the death rate in Turkey and in the world. Especially upper (esophageal and gastric) GI cancers are the leading types of cancer by 20-27% in Eastern Turkey. Trace elements are involved in many physiological and metabolic processes in the human body. Recent studies suggest that the increase or decrease of trace elements in the body may be related to the formation and development of many diseases such as cancers, diabetes mellitus and cardiovascular diseases etc. METHOD AND MATERIALS: In this study some trace elements; cadmium (Cd), cobalt (Co), Copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn) concentrations were investigated in the blood serums of esophageal, gastric and colon cancer patients and healthy controls in Van city area, an endemic upper (esophageal and gastric) GI region of Eastern Turkey. The analysis of the elements was realized with a flame atomic absorption spectrophotometer (FAAS). RESULTS: Mean serum levels of Cd and Ni in esophageal and gastric cancer patients were very significantly lower compared to controls (p < 0.001 and < 0.005). In addition, the mean serum Co level of esophageal cancer patients was very significantly lower than in controls and gastric cancer patients (p < 0.002). Also, the mean serum levels of Fe and Mn in all (esophageal, gastric and colon) cancer groups were very significantly lower than in controls (p < 0.001 and 0.002). Mean serum levels of Cu, Mg, Pb and Zn were not significantly different in all cancer patients compared to controls. CONCLUSION: We have detected the deficiency of five trace elements (Fe, Mn, Cd, Ni, Co) in esophageal, gastric and colon cancer patients. The deficiencies of trace elements may be due to malign over consumption of the nutrients and to the malnutrition of the advanced cancer patients. Nutritional therapy rich in trace elements should be considered as one of the strategies to fight against cancers.

Aleaciones metálicas para aplicaciones ortopédicas: una revisión sobre su respuesta al estrés fisiológico y a los procesos de corrosión

El campo de los biomateriales y sus aplicaciones contribuyen significativamente a la salud y calidad de vida de las personas. Aunque existen varios grupos de biomateriales como cerámicos, polímeros, metales y todos en un determinado porcentaje se utilizan para diferentes procedimientos con objetivos específicos, este artículo de revisión se centra en los metales y sus aleaciones, la resistencia de estos a la corrosión en un entorno biológico y la protección contra el estrés fisiológico. Para esta revisión se seleccionaron artículos que permiten describir dichos aspectos de las aleaciones metálicas utilizadas en aplicaciones ortopédicas partiendo de una detallada búsqueda electrónica, a partir de ello, se concluye que la resistencia a la corrosión y el estrés fisiológico son dos aspectos tan neurálgicos que muchas de las investigaciones realizadas tienen como objetivo mejorarlos garantizando el éxito de la osteosíntesis y la recuperación satisfactoria del paciente. The field of biomaterials and their applications contribute significantly to the health and quality of life of people. Although there are several groups of biomaterials such as ceramics, polymers, metals and all of them in a certain percentage are used for different procedures with specific objectives, this review article focuses on metals and their alloys, their resistance to corrosion in a biological environment and protection against physiological stress. For this review, articles were selected to describe these aspects of metal alloys used in orthopedic applications based on a detailed electronic search. From this, it is concluded that resistance to corrosion and physiological stress are two aspects so crucial that many of the researches carried out aim to improve them to ensure the success of osteosynthesis and the satisfactory recovery of the patient.

Microbial application in remediation of heavy metals: an overview

Heavy metal contamination poses a menacing threat to all living forms in the natural world due to its catastrophic consequences, contributing to environmental pollution. The need for human beings increasing each day along with anthropological activity is contributing directly to the destruction of the environment with the release of a large number of heavy metals into the food chain. These metals can be accumulated in the food chains and are very extremely toxic even at low concentrations. Heavy metals aggregation can deteriorate the healthy ecosystem of the water bodies as well. One of the major concerns is the diminution and administration of the heavy metals aggregating in marine water bodies and lakes. Heavy metals are not degradable and thus tend to remain in the environment for a prolonged time period. Heavy metal aggregation can demonstrate immediate repercussions such as DNA damage, inhibition of respiration and photosynthesis, and rapid reactive oxygen species generation. Conventional or standard chemical and physical methods for remediation of heavy metals are uneconomical and lead to the production of a large magnitude of chemical waste. This shifts the focus and interest towards the utilization of microbes in remediation of heavy metals from the environment which is eco-friendly and economical. To contend with heavy metals, microorganisms have a specific mechanism such as biotransformation, biosorption, and homeostasis. The microbial system is responsive to the toxicity that is created by the heavy metals which are easily water-soluble and available in the environment. The current review article describes the sources and effects of metal ions in the environment followed by bioremediation strategies followed in their remediation. Microbial approaches in remediation of metal ions from extraterrestrial materials are depicted in the paper.

Biomonitoring of Urinary Nickel Successfully Protects Employees and Introduces Effective Interventions

Nickel is a heavy metal used in many industries. Nickel exposure can induce respiratory diseases and allergic reactions, and increase cancer risk. This study evaluated the introduction of a grinding and polishing system to prevent injuries from nickel toxicity in workers. We performed a controlled, interventional, before-and-after study from January 2018 to December 2019 at a faucet component industrial manufacturing site. Results from workplace environmental monitoring, questionnaire responses, and biomonitoring were collected before and after the intervention. Thirty-seven workers (100% men) aged 25.0 (interquartile range (IQR): 22.0–33.5) years were categorized into two groups, those with and without nickel exposure. In the exposed group, the median exposure time was 18.0 months (IQR 14.0–20.0 months). Urinary nickel concentration was lower in the exposed group than in the non-exposed group (13.8 (IQR 1.7–20.7); 23.1 (IQR 11.3–32.8) μg/g creatinine, respectively; p = 0.047). The median urinary nickel concentration was lower in the second year than in the first year (17.4 (IQR 2.2–27.4), 7.7 (IQR 4.3–18.5) μg/g creatinine, respectively; p = 0.022). Significant reductions in urinary nickel concentration were observed following the intervention and educational program. Thus, biomonitoring of urinary nickel concentration can successfully reflect the effectiveness of interventions and their relationship to nickel exposure.

Comparative Study of Potentially Toxic Nickel and Their Potential Human Health Risks in Seafood (Fish and Mollusks) from Peninsular Malaysia

Human exposure to highly nickel (Ni)-polluted environments through oral ingestion pathways may cause various pathological effects. This biomonitoring study aimed to assess the human health risk of potentially toxic Ni in 19 species of marine fishes from Setiu (Terengganu) and two popular seafood molluscs (mangrove snail Cerithidea obtusa and cockle Anadara granosa) from the coastal area of Peninsular Malaysia. The Ni levels of the three seafood types were found below the maximum permissible limit for Ni. The Ni target hazard quotient values of all seafood were lower than 1.00 for average and high-level (AHL) Malaysian consumers, indicating no Ni's non-carcinogenic risk of seafood consumption. It was also found that the calculated values of estimated weekly intake were below than established provisional tolerable weekly intake of Ni for both AHL consumers. It can be concluded that both the AHL consumption of seafood would not pose adverse effects of Ni to the consumers. This study provided a scientific basis for the food safety assessment of Ni and suggestions for risk management of potentially toxic Ni of seafood consumption in Malaysia.

Heavy Metal Contamination of Natural Foods Is a Serious Health Issue: A Review

Heavy metals play an important role in the homeostasis of living cells. However, these elements induce several adverse environmental effects and toxicities, and therefore seriously affect living cells and organisms. In recent years, some heavy metal pollutants have been reported to cause harmful effects on crop quality, and thus affect both food security and human health. For example, chromium, cadmium, copper, lead, and mercury were detected in natural foods. Evidence suggests that these elements are environmental contaminants in natural foods. Consequently, this review highlights the risks of heavy metal contamination of the soil and food crops, and their impact on human health. The data were retrieved from different databases such as Science Direct, PubMed, Google scholar, and the Directory of Open Access Journals. Results show that vegetable and fruit crops grown in polluted soil accumulate higher levels of heavy metals than crops grown in unpolluted soil. Moreover, heavy metals in water, air, and soil can reduce the benefits of eating fruits and vegetables. A healthy diet requires a rational consumption of foods. Physical, chemical, and biological processes have been developed to reduce heavy metal concentration and bioavailability to reduce heavy metal aggregation in the ecosystem. However, mechanisms by which these heavy metals exhibit their action on human health are not well elucidated. In addition, the positive and negative effects of heavy metals are not very well established, suggesting the need for further investigation.

Mechanistic analysis of cadmium toxicity in Saccharomyces cerevisiae

As a potentially toxic heavy metal, Cadmium (Cd) can cause endoplasmic reticulum and oxidative stress, and thus lead to cell death. To explore the mechanisms of Cd toxicity, we investigated the UPRE-lacZ expression, the intracellular reactive oxygen species (ROS) and cell death in the 151 Cd-sensitive mutants of Saccharomyces cerevisiae in response to Cd stress. We identified 101 genes regulating UPRE-lacZ expression were involved in preventing ROS production and/or cell death from increasing to high levels, while mutants for 72 genes caused both elevated ROS production and cell death, indicating the Cd-induced ROS production and cell death are mediated by UPR. Genes involved in cell wall integrity (CWI) pathway, vacuolar protein sorting (VPS) and vacuolar transport, calcium/calcineurin pathway and PHO pathways were all required for the Cd-induced UPR, intracellular ROS and cell death. To conclude, this study highlights the importance of Cd-induced UPR, intracellular ROS levels and cell death that may play crucial roles in Cd-induced toxicity.

TiN/NbN Nanoscale Multilayer Coatings Deposited by High Power Impulse Magnetron Sputtering to Protect Medical-Grade CoCrMo Alloys

This study describes the performance of nanoscale multilayer TiN/NbN coatings deposited on CoCrMo medical-grade alloys by utilising novel mixed high power impulse magnetron sputtering (HIPIMS) and direct current unbalanced magnetron sputtering (UBM) technique in an industrial size vacuum coater. Scanning electron microscopy analysis showed that these coatings were extremely dense without any intercolumnar voids. The coating exhibited high hardness of 28 GPa, as well as low friction and wear coefficient of 0.7 and 1.4 × 10−14 m3·N−1·m−1, respectively, as compared to the bare material. Scratch tests revealed superior coating to substrate adhesion due to the HIPIMS etching prior to coating deposition. Energy-dispersive X-ray analysis of the wear debris generated during the impact test together with focused ion beam cross-section analysis in different locations of the impact crater revealed the coating failure mechanism and further confirmed the excellent coating to substrate bonding strength. Potentiodynamic polarisation tests in NaCl and Hank’s solutions revealed the clear passivation behaviour, several orders of magnitude lower corrosion currents, and high pitting potentials of the coating, which guarantee excellent protection to the base alloy in such aggressive environments. Inductively coupled plasma mass spectrometry analysis of Hank’s solution containing corrosion debris of the coated sample revealed that the leaching of harmful metal ions from the base material was reduced to below the detection limit of the technique, thus demonstrating the high barrier properties of the coating.

Roles of High Osmolarity Glycerol and Cell Wall Integrity Pathways in Cadmium Toxicity in Saccharomyces cerevisiae

Cadmium is a carcinogen that can induce ER stress, DNA damage, oxidative stress and cell death. The yeast mitogen-activated protein kinase (MAPK) signalling pathways paly crucial roles in response to various stresses. Here, we demonstrate that the unfolded protein response (UPR) pathway, the high osmolarity glycerol (HOG) pathway and the cell wall integrity (CWI) pathway are all essential for yeast cells to defend against the cadmium-induced toxicity, including the elevated ROS and cell death levels induced by cadmium. We show that the UPR pathway is required for the cadmium-induced phosphorylation of HOG_MAPK Hog1 but not for CWI_MAPK Slt2, while Slt2 but not Hog1 is required for the activation of the UPR pathway through the transcription factors of Swi6 and Rlm1. Moreover, deletion of HAC1 and IRE1 could promote the nuclear accumulation of Hog1, and increase the cytosolic and bud neck localisation of Slt2, indicating crucial roles of Hog1 and Slt2 in regulating the cellular process in the absence of UPR pathway. Altogether, our findings highlight the significance of these two MAPK pathways of HOG and CWI and their interrelationship with the UPR pathway in responding to cadmium-induced toxicity in budding yeast.

Cobalt–Chromium Dental Alloys: Metal Exposures, Toxicological Risks, CMR Classification, and EU Regulatory Framework

During the 20th century, metal alloys have assumed an important role as restorative materials. Among existing examples, cobalt–chromium (Co–Cr) alloys increasingly began to be used in medicine and especially in dentistry. Their success is mainly due to their mechanical properties such as stiffness, strength and corrosion resistance, thus allowing a high biocompatibility. There are quite meaningful data on the corrosion and toxicity of Co–Cr alloys for their use in restorative materials such as dental prostheses. Toxicological studies following Co and Cr exposures in the oral cavity are more difficult to conduct because there are many different situations leading to the release of metal ions and wear particles. Furthermore, the links between exposure and the appearance of local or systemic toxicity are not automatic. Since 2017, the European Union (EU) regulatory framework for Co–Cr alloys has been undergoing profound changes. A new EU Medical Devices Regulation (MDR) (2017/745) will be applied in May 2021 with the need to consider that Co metal is a new carcinogenic, mutagenic and toxic to reproduction (CMR) substance. On 18 February 2020, the 14th Adaptation to Technical Progress (ATP14) to the Classification, Labelling and Packaging (CLP) regulation was published, including the harmonised classification for Co metal as a CMR 1B substance. In this context, the use of Co might be forbidden if the medical devices are invasive and as soon as they include more than 0.1% (m/m) Co. This review provides a specific overview on Co–Cr dental alloys in terms of metal ions and wear particles release, toxicological risks, and the actual and new EU regulatory framework.

Gene expression in mouse muscle over time after nickel pellet implantation

The transition metal nickel is used in a wide variety of alloys and medical devices. Nickel can cause a range of toxicities from allergy in humans to tumors when implanted in animals. Several microarray studies have examined nickel toxicity, but so far none have comprehensively profiled expression over an extended period. In this work, male mice were implanted with a single nickel pellet in the muscle of the right leg with the left leg used as a control. At 3 week intervals up to 12 months, nickel concentrations in bioflulids and microarrays of surrounding tissue were used to track gene expression patterns. Pellet biocorrosion resulted in varying levels of systemic nickel over time, with peaks of 600 μg L-1 in serum, while global gene expression was cyclical in nature with immune related genes topping the list of overexpressed genes. IPA and KEGG pathway analyses was used to attribute overall biological function to changes in gene expression levels, supported by GO enrichment analysis. IPA pathways identified sirtuin, mitochondria, and oxidative phosphorylation as top pathways, based predominantly on downregulated genes, whereas immune processes were associated with upregulated genes. Top KEGG pathways identified were lysosome, osteoclast differentiation, and phasgosome. Both pathway approaches identified common immune responses, as well as hypoxia, toll like receptor, and matrix metalloproteinases. Overall, pathway analysis identified a negative impact on energy metabolism, and a positive impact on immune function, in particular the acute phase response. Inside the cell the impacts were on mitochondria and lysosome. New pathways and genes responsive to nickel were identified from the large dataset in this study which represents the first long-term analysis of the effects of chronic nickel exposure on global gene expression.

Mineralogical and Geochemical Characterization of Asbestiform Todorokite, Birnessite, and Ranciéite, and Their host Mn-Rich Deposits from Serra D’Aiello (Southern Italy)

Manganese ores, especially the oxyhydroxides in their different forms, are the dominant Mn-bearing minerals that occur in marine and terrestrial environments, where they are typically found as poorly crystalline and intermixed phases. Mn oxyhydroxides have a huge range of industrial applications and are able to exert a strong control on the mobility of trace metals. This paper reports the results of a detailed study on the Mn oxyhydroxides occurring in the manganiferous deposit outcropping in the Messinian sediments from Serra D’Aiello (Southern Italy). Nine Mn samples were characterized in detail using X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), thermogravimetry (TG), transmission electron microscopy combined with energy dispersive spectrometry (TEM/EDS), and X-ray fluorescence (XRF). The results indicated that the Mn deposit included the oxyhydroxide mineral species birnessite, todorokite, and rancièite. The size, morphology, and chemical composition of Mn oxyhydroxide samples were investigated in order to define their impact on the environment and human health. Todorokite displayed asbestiform shapes and could disperse fibers of breathable size in the air. Furthermore, since in-depth characterization of minerals within Mn deposits may be the first step toward understanding the genetic processes of manganese deposits, hypotheses about the genesis of the Mn oxyhydroxide deposits were discussed.

Nickel: Human Health and Environmental Toxicology

Nickel is a transition element extensively distributed in the environment, air, water, and soil. It may derive from natural sources and anthropogenic activity. Although nickel is ubiquitous in the environment, its functional role as a trace element for animals and human beings has not been yet recognized. Environmental pollution from nickel may be due to industry, the use of liquid and solid fuels, as well as municipal and industrial waste. Nickel contact can cause a variety of side effects on human health, such as allergy, cardiovascular and kidney diseases, lung fibrosis, lung and nasal cancer. Although the molecular mechanisms of nickel-induced toxicity are not yet clear, mitochondrial dysfunctions and oxidative stress are thought to have a primary and crucial role in the toxicity of this metal. Recently, researchers, trying to characterize the capability of nickel to induce cancer, have found out that epigenetic alterations induced by nickel exposure can perturb the genome. The purpose of this review is to describe the chemical features of nickel in human beings and the mechanisms of its toxicity. Furthermore, the attention is focused on strategies to remove nickel from the environment, such as phytoremediation and phytomining.

Cancer Risk After Midurethral Sling Surgery Using Polypropylene Mesh

OBJECTIVE

To assess whether there is any association between the implantation of synthetic polypropylene mesh slings for the treatment of stress urinary incontinence (SUI) and risk of cancer.

METHODS

We performed a nationwide cohort study based on the general female population in Sweden. All women entered the observational period as unexposed on January 1, 1997, and contributed person-time as unexposed unless they underwent a midurethral sling procedure for SUI, after which they contributed person-time as exposed until first occurrence of any cancer, death, emigration, or end of the observational period (December 31, 2009). Occurrence of primary cancer was ascertained from the Cancer Register. Hazard ratios (HRs) with 95% CIs were calculated by Cox proportional hazards regression.

RESULTS

The final study population included 5,385,186 women, including 20,905 exposed, encompassing a total of 44,012,936 person-years at risk. Other than an inverse association with rectal cancer (HR 0.5, 95% CI 0.3-0.8), there were no significant differences in risk between exposed and unexposed women for pelvic organ cancers including ovarian (HR 0.8, 95% CI 0.5-1.2), endometrial (HR 1.1, 95% CI 0.8-1.4), cervical (HR 0.4, 95% CI 0.2-1.0), bladder, and urethra (HR 0.7, 95% CI 0.4-1.2). No significant association was observed between exposed women and primary cancer in any organ system when compared with unexposed women. The relative risk for cancer after exposure showed little variation over time except for an inverse overall correlation within the first 4 years of surgery (HR 0.7, 95% CI 0.7-0.8). The incidence rates per 100,000 person-years (95% CIs) for exposed vs unexposed women were 20.5 (14.3-29.5) vs 21.0 (20.6-21.5) for rectal cancer, 25.5 (18.4-35.3) vs 19.8 (19.4-20.2) for ovarian cancer, 65.0 (53.0-79.8) vs 33.1 (32.6-33.7) for endometrial cancer, 5.7 (2.8-11.3) vs 11.9 (11.6-12.2) for cervical cancer, and 19.1 (13.1-27.8) vs 13.3 (13.0-13.7) for bladder and urethra cancer.

CONCLUSION

Our results suggest that midurethral polypropylene sling surgery for SUI is not associated with an increased cancer risk later in life.

Microstructure, mechanical properties and springback behaviour of Ti‑6Al‑4V alloy connection rod for spinal fixation device

The effect of annealing condition on microstructure, mechanical properties and springback behaviour was examined in the connection rod of Ti-6Al-4V alloy for spinal fixation devices. Compared with the deformed microstructure in the sample before annealing, relatively few equiaxed grains were present after annealing at 1003 K after 1.8 ks, and a considerable amount appeared at 7.2 ks. When annealing time was extended to 36 ks, the recrystallised grains further grew. Vickers hardness, tensile strength and bending strength decreased with increasing annealing time, whereas the elastic and bending moduli showed no significant change with annealing time of up to 7.2 ks and then slightly decreased at 36 ks. The springback ratio was closely associated with strength and modulus and applied bending deflection. The springback ratio reached the highest and lowest values in the sample before and after annealing for 7.2 ks, respectively. A good combination of strength, modulus and springback ratio was obtained in the sample after annealing for 7.2 ks.

A Silk Cranial Fixation System for Neurosurgery

Cranial fixation should be safe, reliable, ideally degradable, and produce no hazardous residues and no artifacts on neuroimaging. Protein-based fixation devices offer an exciting opportunity for this application. Here, the preclinical development and in vivo efficacy verification of a silk cranial fixation system in functional models are reported by addressing key challenges toward clinical use. A comprehensive study on this fixation system in rodent and canine animal models for up to 12 months is carried out. The silk fixation system shows a superb performance on the long-term stability of the internal structural support for cranial flap fixation and bone reconnection and has good magnetic resonance imaging compatibility, and tolerability to high dose radiotherapy, underscoring the favorable clinical application of this system for neurosurgery compared to the current gold standard.

Toxic Metal Pollution in Pakistan and Its Possible Risks to Public Health

Environmental pollution has increased many folds in recent years and in some places has reached levels that are toxic to living things. Among pollutant types, toxic heavy metals and metalloids are among the chemicals that pose the highest threat to biological systems (Jjemba 2004). Unlike organic pollutants, which are biodegradable, heavy metals are not degraded into less hazardous end products (Gupta et al. 2001). Low concentrations of some heavy metals are essential for life, but some of them like Hg, As, Pb and Cd are biologically non-essential and very toxic to living organisms. Even the essential metals may become toxic if they are present at a concentration above the permissible level (Puttaiah and Kiran 2008). For example, exposure to Zn and Fe oxides produce gastric disorder and vomiting, irritation of the skin and mucous membranes. Intake of Ni, Cr, Pb, Cd and Cu causes heart problems, leukemia and cancer, while Co and Mg can cause anemia and hypertension (Drasch et al. 2006). Similarly, various studies indicated that overexposure to heavy metals in air can cause cardiovascular disorders (Miller et al. 2007; Schwartz 2001), asthma (Wiwatanadate and Liwsrisakun 2011), bronchitis/emphysema (Pope 2000), and other respiratory diseases (Dominici et al. 2006).

L-Ascorbic Acid Protected Against Extrinsic and Intrinsic Apoptosis Induced by Cobalt Nanoparticles Through ROS Attenuation

Currently, tissue damage induced by cobalt nanoparticles (CoNPs) and cobalt ions (Co²⁺) are the most serious syndrome in the patients with metal-on-metal hip prostheses. Therefore, an urgent need exists for the identification of the mechanisms and the development of therapeutic strategies to limit it. The purpose of this study was to explore the mechanism of this damage and to demonstrate if L-ascorbic acid (L-AA) could protect against the cell toxicities induced by CoNPs and Co²⁺ in vitro. With CoNPs and Co²⁺ treatment, cell viability was significantly decreased; the ROS (reactive oxygen species) level in mitochondria was dramatically increased in CoNPs treated cells, but cobalt ions could barely induce the ROS. Consistently, the level of cell apoptosis was increased with the upregulation of pro-apoptotic factors (caspases 8, 9, and 3, and Bax) and the downregulation of anti-apoptotic factor Bcl-2. Besides that, the levels of cytochrome c and AIF were increased and released from mitochondria into the cytoplasm. After the cells were pretreated with L-AA, the cell viability decreased by CoNPs was reversed and the ROS induced by CoNPs was suppressed. The level of cell apoptosis induced by CoNPs was decreased as well. But it could not reverse the effects induced by Co²⁺. These studies demonstrated that CoNPs induce extrinsic and intrinsic apoptotic pathways via generation of ROS, and L-AA could prevent the cytotoxicity by reducing the level of ROS. While Co²⁺ may induce cytotoxicity through other signals, it could not be protected by L-AA treatment.

Carcinogenic potential of polypropylene mid-urethral slings: what do we know so far?

INTRODUCTION AND HYPOTHESIS

Polypropylene (PP) mesh has come under increased scrutiny owing to previous FDA safety communications regarding the risks of mesh in trans-vaginal surgery and ensuing class action litigation for post-operative complications. Additional concerns have been raised regarding a possible link between implanted PP mesh and the long-term development of malignancy. Until recently, no research was specifically committed to the exploration of such a link. Our objective was to provide an overview of the recent literature focusing on any association between the use of PP mesh for midurethral sling procedures and the development of malignancy.

METHODS

Multiple online research databases were searched for information related to any possible carcinogenic potential of PP mesh.

RESULTS

There was no increased incidence in the development of malignancy after midurethral sling procedures using PP mesh in any of the studies.

CONCLUSION

Given the scarcity of evidence suggesting otherwise, the likelihood of PP mesh causing malignancy is exceptionally low. However, with few studies and an unknown latency period between exposure and diagnosis, more observational data would prove useful to exclude causality.

Biodegradable Metals for Cardiovascular Stents: from Clinical Concerns to Recent Zn-Alloys

Metallic stents are used to promote revascularization and maintain patency of plaqued or damaged arteries following balloon angioplasty. To mitigate the long-term side effects associated with corrosion-resistant stents (i.e., chronic inflammation and late stage thrombosis), a new generation of so-called "bioabsorbable" stents is currently being developed. The bioabsorbable coronary stents will corrode and be absorbed by the artery after completing their task as vascular scaffolding. Research spanning the last two decades has focused on biodegradable polymeric, iron-based, and magnesium-based stent materials. The inherent mechanical and surface properties of metals make them more attractive stent material candidates than their polymeric counterparts. A third class of metallic bioabsorbable materials that are based on zinc has been introduced in the last few years. This new zinc-based class of materials demonstrates the potential for an absorbable metallic stent with the mechanical and biodegradation characteristics required for optimal stent performance. This review compares bioabsorbable materials and summarizes progress towards bioabsorbable stents. It emphasizes the current understanding of physiological and biological benefits of zinc and its biocompatibility. Finally, the review provides an outlook on challenges in designing zinc-based stents of optimal mechanical properties and biodegradation rate.

Oral cancer or periimplantitis: A clinical dilemma

The purpose of this article was to draw attention to a periimplantitis-like clinical presentation of oral malignancy around dental implants, a phenomenon that may develop without any associated risk factors for oral cancer. Such a benign appearance of oral malignancy may lead to delay in the diagnosis and initiation of ensuing treatment. Therefore, chronic nonhealing inflammatory lesions around dental implants should be considered as highly suspicious.

Wear Characteristics of Metallic Biomaterials: A Review

Metals are extensively used in a variety of applications in the medical field for internal support and biological tissue replacements, such as joint replacements, dental roots, orthopedic fixation, and stents. The metals and alloys that are primarily used in biomedical applications are stainless steels, Co alloys, and Ti alloys. The service period of a metallic biomaterial is determined by its abrasion and wear resistance. A reduction in the wear resistance of the implant results in the release of incompatible metal ions into the body that loosen the implant. In addition, several reactions may occur because of the deposition of wear debris in tissue. Therefore, developing biomaterials with high wear resistance is critical to ensuring a long life for the biomaterial. The aim of this work is to review the current state of knowledge of the wear of metallic biomaterials and how wear is affected by the material properties and conditions in terms of the type of alloys developed and fabrication processes. We also present a brief evaluation of various experimental test techniques and wear characterization techniques that are used to determine the tribological performance of metallic biomaterials.

Investigating the biological response of human mesenchymal stem cells to titanium surfaces

BACKGROUND

We have investigated the behaviour of a newly characterised population of haemarthrosis fluid-derived human mesenchymal stem cells (HF-hMSCs) with titanium (Ti) surfaces.

METHODS

HF-hMSCs were seeded onto round cannulated interference (RCI; Smith and Nephew) screws or control Ti discs and cultured under pro-osteogenic conditions.

RESULTS

Electron microscopy showed the attachment and spreading of HF-hMSCs across both Ti surfaces during the early stages of osteogenic culture; however, cells were exclusively localised to the basal regions within the vertex of the Ti screws. In the later stages of culture, an osteoid matrix was deposited on the Ti surfaces with progressive culture expansion and matrix deposition up the sides and the top of the Ti Screws. Quantification of cellular content revealed a significantly higher number of cells within the Ti screw cultures; however, there was no difference in the cellular health. Conversely, alizarin red staining used as both a qualitative and quantitative measure of matrix calcification was significantly increased in Ti disc cultures compared to those of Ti screws.

CONCLUSIONS

Our results suggest that the gross topography of the metal implant is able to create microenvironment niches that have an influence on cellular behaviour. These results have implications for the design of advanced tissue engineering strategies that seek to use cellular material to enhance biological remodelling and healing following tissue reconstruction.

Polypropylene mesh: evidence for lack of carcinogenicity

Tumors related to the implantation of surgical grade polypropylene in humans have never been reported. In this commentary we present a balanced review of the information on what is known regarding the host response to polypropylene and provide data as to why the potential for carcinogenicity of polypropylene mesh is exceedingly small.

Application of bone marrow and adipose-derived mesenchymal stem cells for testing the biocompatibility of metal-based biomaterials functionalized with ascorbic acid

In this study, metal-based biomaterials were functionalized with ascorbic acid (LAA). Two types of substrates were used: austenitic steel 316L and titanium Ti6Al4V. Coatings were prepared with the sol-gel method and applied on metal surfaces using the dip-coating technique. Ascorbic acid was delivered with SiO2-coating at concentrations of 0.1 and 0.4 M. The morphology of the surfaces and coatings was determined using scanning electron microscope (SEM), whereas their elemental composition by SEM-EDX. Immobilization of ascorbic acid in the coatings was confirmed with Raman spectroscopy. The biocompatibility of the materials obtained was tested in vitro using both bone marrow- and adipose-derived mesenchymal stem cells (BMMSC and ADMSC, respectively). Proliferation rate and morphology of cells cultured in the presence of designed biomaterials were monitored after 24, 48, 120 and 168 h of propagation. The results obtained indicated that silica coatings doped with 0.4 M LAA had a positive effect on the proliferation rate of investigated cells, and in some cases on the growth pattern of culture.