China
Africa
Explore chapters and articles related to this topic
Contrast enhancement agents and radiopharmaceuticals
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
The LD50 value is a number assigned to a pharmaceutical compound during development stages in clinical trials and relates to the median lethal dose for the substance to kill 50% of the test population. The free gadolinium ion has an LD50 of approximately 100–200 mg/kg, yet the LD50 is increased by a factor of 100 when the gadolinium is chelated. It is important to evaluate every patient and product for potential adverse side-effects before administering the contrast agent.
Occupational Toxicology
Published in Lorris G. Cockerham, Barbara S. Shane, Basic Environmental Toxicology, 2019
Since another chapter in this text provides an in-depth discussion of animal bioassay methodology, only a brief review of pertinent studies important in occupational toxicology are reviewed here. Acute toxicity tests are usually the first studies to be performed. They determine the toxic effects (usually lethality) resulting from a brief single exposure. They establish the toxicity of the test substance relative to other chemical substances and may provide information on the mode of toxic action, median lethal dose (LD50), and differences in toxic response as related to sex and route of exposure. Groups of animals are administered single doses (at least three dose level groups are used) and are observed for 14 d.
Health Hazard Characterization
Published in George G. Lowry, Robert C. Lowry, Handbook of Hazard Communication and OSHA Requirements, 2017
George G. Lowry, Robert C. Lowry
The terms LD50 and LC50 refer to the dose and concentration, respectively, at which one half of the test animals died, also known as the median lethal dose (and concentration). At higher doses, more than half of the animals died, and at lower doses, fewer. However, frequently the values of LD50 or LC50 given in the literature for a particular compound were measured for a different animal species than indicated in these definitions, or under different exposure rates than specified. In such cases, approximate translations can be made, but they are always subject to significant error. See Appendix 4 for a discussion of lethal dose equivalencies.
Random forest algorithm-based accurate prediction of rat acute oral toxicity
Published in Molecular Physics, 2022
Linrong Xiao, Jiyong Deng, Liping Yang, Xianwei Huang, Xinliang Yu
Determining acute toxicity of chemicals in mammals (e.g. rats or mice) is labor-intensive, high monetary and time cost. Furthermore, it is impossible to determine the toxicity of all chemicals [4,5]. Quantitative structure–activity relationship (QSAR)/quantitative structure–toxicity relationship models can be used for predicting the acute oral toxicity endpoint for compounds [6–10], even without necessarily carrying out their chemical synthesis. This methodology has been proposed in risk assessment by some regulations and guidelines like the European Union Registration, Evaluation and Authorization of Chemicals (EU REACH) Legislation, the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) M7 guideline, the United States Food & Drug Administration (US FDA) and the United States Environmental Protection Agency (US EPA) [11–14]. Mice and rats are by far the most common species used for experimental purposes [15–19]. The median lethal dose LD50 denotes the dose of a chemical resulting in 50% of mortality for a test group in a short amount of time (generally less than 24 h) [6,20]. Rat acute oral LD50 can serve useful functions and have practical implications. It has become a standard piece of information in categorising compounds in terms of the potential hazard affecting human health after acute exposure.
Uptake of cyanide compounds from aqueous solutions by lemon peel with utilising the residue absorbent as rodenticide
Published in Indian Chemical Engineer, 2020
Hayder A. Alalwan, Mohammad N. Abbas, Alaa H. Alminshid
The results of testing used lemon peel as a rodenticide showed that there were significant fatalities among both genders of rats fed lemon peel saturated with CN−. The fatalities occurred at various ratios and times depending on the amount of rodenticide consumed by rats. The median lethal dose (LD50), which is the toxin dose wanted to kill half of the members of the examined samples, rats in this investigation, was also calculated, and the results showed that there were no fatalities in both controlling groups. LD50 express the amount of toxin (in mg) per the body weight (in kg) of dead animals. Based on the calculating of the amount of cyanide consumed by all rats and the weight of the death rats, the value of LD50 was found to be 5.53 (mg/kg) for male and 5.17 (mg/kg) for female and these matched those cited in the literature (between 5 and 5.72).