About: Zinc toxicity is a(n) research topic. Over the lifetime, 727 publication(s) have been published within this topic receiving 34583 citation(s). The topic is also known as: zinc poisoning.
Papers published on a yearly basis
TL;DR: The use of zinc in medicinal skin cream was mentioned in Egyptian papyri from 2000 BC, and the number of biological functions, health implications and pharmacological targets that are emerging for zinc indicate that it might turn out to be 'the calcium of the twenty-first century'.
Abstract: The use of zinc in medicinal skin cream was mentioned in Egyptian papyri from 2000 BC (for example, the Smith Papyrus), and zinc has apparently been used fairly steadily throughout Roman and modern times (for example, as the American lotion named for its zinc ore, 'Calamine'). It is, therefore, somewhat ironic that zinc is a relatively late addition to the pantheon of signal ions in biology and medicine. However, the number of biological functions, health implications and pharmacological targets that are emerging for zinc indicate that it might turn out to be 'the calcium of the twenty-first century'.
TL;DR: A multidisciplinary approach will most likely result in success in the pharmacology of zinc compounds as a promising area for translational research, and the current assumed range between safe and unsafe intakes of zinc is relatively narrow.
Abstract: The adult human contains 2-3g of zinc, about 0.1% of which are replenished daily. On this basis and based on estimates of bioavailability of zinc, dietary recommendations are made for apparently healthy individuals. Absent chemical, functional, and/or physical signs of zinc deficiency are assumed indicative of adequacy. More specific data are seldom available. Changing food preferences and availability, and new food preparation, preservation, and processing technologies may require re-evaluation of past data. Conservative estimates suggest that 25% of the world's population is at risk of zinc deficiency. Most of the affected are poor, and rarely consume foods rich in highly bioavailable zinc, while subsisting on foods that are rich in inhibitors of zinc absorption and/or contain relatively small amounts of bioavailable zinc. In contrast, among the relatively affluent, food choice is a major factor affecting risk of zinc deficiency. An additional problem, especially among the relatively affluent, is risk of chronic zinc toxicity caused by excessive consumption of zinc supplements. High intakes of zinc relative to copper can cause copper deficiency. A major challenge that has not been resolved for maximum health benefit is the proximity of the recommended dietary allowance (RDA) and the reference dose (RfD) for safe intake of zinc. Present recommendations do not consider the numerous dietary factors that influence the bioavailability of zinc and copper, and the likelihood of toxicity from zinc supplements. Thus the current assumed range between safe and unsafe intakes of zinc is relatively narrow. At present, assessment of zinc nutriture is complex, involving a number of chemical and functional measurements that have limitations in sensitivity and specificity. This approach needs to be enhanced so that zinc deficiency or excess can be detected early. An increasing number of associations between diseases and zinc status and apparently normal states of health, where additional zinc might be efficacious to prevent certain conditions, point at the pharmacology of zinc compounds as a promising area. For example, relationships between zinc and diabetes mellitus are an area where research might prove fruitful. In our opinion, a multidisciplinary approach will most likely result in success in this fertile area for translational research.
01 Jan 2004
TL;DR: This chapter discusses dietary sources of zinc and factors affecting the proportion of zinc available for absorption in the diet, as well as causes of zinc deficiency and groups at high risk.
Abstract: Chapter 1: Overview of Zinc Nutrition S99 1.1 Biological functions of zinc S99 1.2 Tissue zinc distribution and reserves S99 1.3 Zinc metabolism S100 1.4 Importance of zinc for human health S101 1.5 Human zinc requirements S105 1.5.1 Adult men S106 1.5.2 Adult women S109 1.5.3 Children S110 1.5.4 Pregnancy S111 1.5.5 Lactation S112 1.6 Dietary sources of zinc and suggested revisions of Recommended Daily Intakes S112 1.6.1 Dietary sources of zinc and factors affecting the proportion of zinc available for absorption ........ S112 1.6.2 Revised estimates of dietary requirements and recommended intakes for zinc S114 1.7 Zinc toxicity S118 1.8 Causes of zinc deficiency and groups at high risk S121 1.9 Summary S123
TL;DR: It is proposed that ZnT‐1 transports zinc out of cells and that its absence accounts for the increased sensitivity of mutant cells to zinc toxicity.
Abstract: A cDNA encoding a zinc transporter (ZnT-1) was isolated from a rat kidney cDNA expression library by complementation of a mutated, zinc-sensitive BHK cell line. This cDNA was used to isolate the homologous mouse ZnT-1 gene. The proteins predicted for these transporters contain six membrane-spanning domains, a large intracellular loop and a C-terminal tail. ZnT-1 is homologous to zinc and cobalt resistance genes of yeast. Immunocytochemistry with an antibody to a myc epitope added to the C-terminus of ZnT-1 revealed localization to the plasma membrane. Transformation of normal cells with a mutant ZnT-1 lacking the first membrane-spanning domain conferred zinc sensitivity on wild-type cells, suggesting that ZnT-1 functions as a multimer. Deletion of the first two membrane-spanning domains resulted in a non-functional molecule, whereas deletion of the C-terminal tail produced a toxic phenotype. Mutant cells have a slightly higher steady-state level of intracellular zinc and high basal expression of a zinc-dependent reporter gene compared with normal cells. Mutant cells have a lower turnover of 65Zn compared with normal cells or mutant cells transformed with ZnT-1. We propose that ZnT-1 transports zinc out of cells and that its absence accounts for the increased sensitivity of mutant cells to zinc toxicity.
TL;DR: It is suggested that ZnT‐2 protects zinc‐sensitive BHK cells from zinc toxicity by facilitating zinc transport into an endosomal/lysosomal compartment.
Abstract: A cDNA encoding a second zinc transporter (ZnT-2) was isolated from a rat kidney cDNA expression library by complementation of a zinc-sensitive BHK cell line. The protein predicted from the open reading frame of ZnT-2 cDNA has 359 amino acids and initiates with a CTG codon. It resembles ZnT-1 (a plasma membrane protein that stimulates zinc efflux) in overall topology in that it has six membrane-spanning domains, a histidine-rich intracellular loop and a long C-terminal tail; however, the overall amino acid identity is only 26%. Unlike ZnT-1, which is in the plasma membrane and lowers cellular zinc by stimulating zinc efflux, ZnT-2 is localized on vesicles and allows the zinc-sensitive BHK cells to accumulate zinc to levels that are much higher than non-transformed cells can tolerate. Zinc was visualized within these vesicles with zinquin, a zinc-specific fluorescent probe. The intracellular compartment that accumulates zinc is acidic as revealed by staining with acridine orange or LysoTracker. Prolonged exposure of cells expressing ZnT-2 to zinc causes an accretion of intracellular vesicles. We suggest that ZnT-2 protects these cells from zinc toxicity by facilitating zinc transport into an endosomal/lysosomal compartment.
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