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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.
Health and safety in the laboratory
Published in Maxine Lintern, Laboratory Skills for Science and Medicine, 2018
Important information about how that chemical is or may become dangerous is also included in the assessment. For example, a compound that produces toxic fumes would need to be handled exclusively in a fume hood of appropriate rating; a skin absorbable poison would be handled wearing special gloves. Most compounds also have a ‘LD50’ to guide you. This is a statement of how much of this compound was required to give a ‘lethal dose’ to half a cohort of (usually) rats. LD50 data can show relative risks between compounds, and human LD50 information is available for some compounds. Pharmaceutical companies produce similar data for drugs and medicines.
Toxicology
Published in Aruna Bakhru, Nutrition and Integrative Medicine, 2018
Like any field of science, toxicology has its own abbreviations and phrases. LD50 is a useful term that refers to the dose of a substance that displays toxicity in that it kills 50% of a test population. In scientific research, rats or other surrogates are usually used to determine toxicity. The data are then extrapolated for humans.
Surface-modified vacuole-based daunorubicin delivery system for acute myeloid leukaemia (AML) and their selective therapeutics
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2022
Wooil Choi, Yang-Hoon Kim, Jiho Min
To prevent the side effect of crude chemotherapeutics, the drug delivery system based on recombinant vacuoles was evaluated. After decoration with HL-60 cell targeting peptide, cell mortality was compared with free daunorubicin (DNR), nontargeting DNR loaded vacuoles, and targeting DNR-loaded vacuoles in Figure 6. The results show that the cell mortality of targeting vacuoles with encapsulated DNR is clearly more efficient than the crude daunorubicin and nontargeting vacuoles. Also, the results show the synergetic effects of targeting vacuoles and daunorubicin. According to these results, the value of lethal concentration 50 (LC50) can be compared. LC50 of free daunorubicin (LC50 free DNR) is about 1 µg/mL for 6 h exposure. In comparison, LC50 of targeting vacuoles (LC50 targeting vacuoles) is lower than half of LC50 free DNR. This means that the amount of drug needed to kill the same amount of cancer cells is reduced to less than half. Comparison of the LC50 of nontargeting vacuoles (LC50 nontargeting vacuoles) and LC50 targeting vacuoles shows that targeting peptide improved the efficacy of drug delivery.
Assesment of hematotoxic, oxidative and genotoxic damage potentials of fipronil in rainbow trout Oncorhynchus mykiss, Walbaum
Published in Toxicology Mechanisms and Methods, 2021
Arzu Uçar, Veysel Parlak, Aslı Çilingir Yeltekin, Fatma Betül Özgeriş, Özge Çağlar, Hasan Türkez, Gonca Alak, Muhammed Atamanalp
160 rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) (120 ± 5 g; 20 ± 2 cm) which produced at Atatürk University Inland Water Fish Application and Research Unit were taken to the experimental environment. The research is designed as two replications with three different dosage and control groups. Eight glass aquariums (40 × 75 × 50 cm/150 l volume) were used as the experiment medium. The physicochemical properties of water (daily temperature, oxygen, and pH values) were suitable for O. mykiss. It was determined as pH from 7.0, from 8 to 9 mg/L dissolved oxygen, 10.5 ± 0.5 °C temperature, and 220 mg/L of total hardness. Fipronil was obtained from a commercial company (Akdeniz chemistry, Erzurum). After 14 days of acclimation period, fish were exposed to the three different doses of the pesticide for 4 days. The LC50 value for rainbow trout is 0.246 mg/L, determined by Chandler et al. (2004). In this direction, application doses were determined as: 0.05 mg/L; 20% of LC50, 0.1 mg/L; 40% of LC50, and 0.2 mg/L; 80% of LC50.
Evaluation of interactive effects of UV light and nano encapsulation on the toxicity of azoxystrobin on zebrafish
Published in Nanotoxicology, 2020
Yueyang Zhang, Claudia Sheedy, Denise Nilsson, Greg G. Goss
The 96 h-LC50 of Az (1031 μg L−1 nominal concentration) without UV exposure was similar to the published 96 h-LC50 value (1230 μg L−1) for zebrafish embryos (Jia et al. 2018) while the 96 h-LC50 of nAz (334 μg L−1) was found to be much lower. The published LC50 of 1230 μg/L was based on nominal concentrations and this is why we have included our nominal concentration for comparison. However, the LC50 values of nAz and Az based on measured concentrations were lower than those for nominal concentrations. This suggests that regulations should follow a LC50 with measured concentrations. The hatching success was significantly decreased when zebrafish embryos were exposed to the concentrations close to or above LC50 value mainly due to the death of embryos at those concentrations while no significant reduction on final hatching success was observed at low concentrations (Supplementary Material Figure S5). Therefore, the direct effect of Az on zebrafish hatching success is negligible.