China
Africa
Explore chapters and articles related to this topic
Metal Exposure and Toxic Responses
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
Aluminum is presently considered a nonessential element in humans. A variety of biochemical interactions with aluminum have been investigated. Many of these effects pertain to aluminum neurotoxicity. Acute neurological disorders termed “dialysis dementia” or “dialysis encephalopathy” have been reported in chronic hemodialysis patients. Patients developing such neurological disorders have been shown to have high levels of aluminum in their serum and brain tissue. Perhaps the most intriguing and potentially significant aspect of aluminum toxicity is the evidence implicating aluminum in the pathogenesis of Alzheimer’s disease, an insidious neurodegenerative disorder of unknown etiology for which there is no effective treatment or cure.
List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
The common routes of human exposure to aluminum are ingestion and inhalation. Exposures to aluminum cause different signs and symptoms of toxicity that include, but are not limited to, burning pain in the head, throbbing headache with constipation, vertigo, nausea, hair loss, eyes feel cold, dry, burning, chronic conjunctivitis, humming in the ears, facial pimples, sore and bleeding gums, abnormal cravings for chalk, charcoal, dry food, pain in arms and fingers, restless and anxious sleep and dreams, chapped skin, and brittle nails. Also, aluminum has been shown to be a risk factor in the onset of neurological diseases, notably Alzheimer’s disease and other dementias. Therefore, it is important to stop contamination from all potential aluminum sources. Acute toxicity related to aluminum is extremely rare. However, aluminum toxicity is usually found among patients with impaired renal function. Reports have shown that aluminum causes conjunctivitis, eczema, upper airway irritation, pneumoconio-sis, and especially with dialysis patients, neurotoxicity and osteomalacia. For years, elevated aluminum has been implicated in several brain diseases, such as Alzheimer’s and Parkinson’s disease, and has also been found in some senior citizens with extreme memory loss, absent-mindedness, or dementia. It is sometimes found in the hair of children diagnosed with ADHD, ADD, and those with seizures. Hyperactivity, memory disturbances, and learning disabilities may result from even mildly elevated levels of aluminum. Inhibition of neurotransmission and impaired motor coordination may also result. According to a report in the Lancetin 1989, many infant formulas contain aluminum. In this report, it was revealed that human breast milk contained 5-20 Ug/L of aluminum, cow’s milk-based formulas contained 20 times as much aluminum, and soy-based formulas contained 100 times as much. Physical symptoms of aluminum tox-icity include brittle bones or osteoporosis, as aluminum is stored in the bones. Kidney malfunction may also result, as the kidneys filter aluminum. Toxicity of aluminum and its association with Alzheimer’s disease in humans has not been well confirmed since some data are against while other data are inadequate and inconclusive.
Investigations on the corrosion behaviour and biocompatibility of magnesium alloy surface composites AZ91D-ZrO2 fabricated by friction stir processing
Published in Transactions of the IMF, 2019
R. Vaira Vignesh, R. Padmanaban, M. Govindaraju, G. Suganya Priyadharshini
The in vitro studies of biomedical magnesium alloys in simulated body fluid (SBF) reveal that the following alloys are biocompatible: Mg-Al-Zn, Mg–Ca, Mg-Zn-Ca, Mg-Zn-Mn-Ca, Mg-Si-Ca, Mg-Zn, Mg-Zn-Mn, Mg-Mn, LAE42, WE43, ZE41, AE44, Mg-Gd, WZ21, and Mg-Y.8,9 In this study, AZ91D alloy (Mg-Al-Zn alloy system) has been chosen as the base material. The authors have observed a series of discussions in research forums on the association of aluminium with Alzheimer’s disease. The authors find no consistent and compelling evidence to associate aluminium with Alzheimer’s disease. Though a few studies have found associations between the aluminium levels and Alzheimer’s risk, many others found no such associations. An article by the Food and Drug Administration (FDA) agency states that the issue of aluminium toxicity and Alzheimer’s disease remains controversial and is not resolved. In addition, the agency considers the evidence to link aluminium to Alzheimer’s disease, Parkinson’s disease or amyotrophic lateral sclerosis (ALS), also known as motor neurone disease (MND), is insufficient. An article by Dementia Australia states that there are no consistent reports that correlate aluminium exposure with Alzheimer’s disease and the majority of elderly people do not get Alzheimer’s disease. In addition, AZ91D alloy has been chosen as base material in a wide range of research on biodegradable implants. Hence, AZ91D alloy is chosen as the base material in this study.
Vehicle pollution toxicity induced changes in physiology, defence system and biochemical characteristics of Calotropis procera L.
Published in Chemistry and Ecology, 2018
Noreen Khalid, Ali Noman, Tayyaba Sanaullah, Muhammad Adnan Akram, Muhammad Aqeel
The Amount of total free amino acids and total antioxidant activity was increased in this study. The results are in conformity with the previous researchers for other plants species [68–72]. Highest free amino acid contents were noted at the Adda-46 and Pull-111 sites and might be due to additional stress caused by air pollutants associated with high vehicular density at these sites. Concentrations of various plant metabolites (i.e. polyamines, proline, glutamine, glutamic acid, glycine, alanine, valine, serine, antioxidants, nicotianamine and other free amino acids) increase in concentrations due to the effect of various air pollutants. These metabolites help reduce stress through binding to toxic metallic particles. Activation of the defence system of plants causes accumulation of metabolites [73]. Hence, increased concentrations of free amino acids and antioxidant activity in C. procera were probably due to activation of its defence system to cope with the stress impacts caused by the polluted environment. According to Power and Collins [74], the amount of free amino acids in plants along roadsides is directly related to the amount of nitrogen deposition from vehicular exhausts. Particulate matter present in vehicular emissions causes changes in amino acid concentrations in plants [75]. Various antioxidant enzymes were found to be activated in Vicia faba with increased soil Pb concentrations [76]. Lemna minor also upregulated its antioxidant defence system due to zinc and aluminium toxicity [77]. Reactive oxygen species (ROS) produced in plants in response to SO2 stress results in activation of the antioxidant defence system in lettuce. Antioxidant defence system plays an important role in plant protection against oxidative stress caused by SO2 [78].