Cell models in the study of mechanisms of toxicity

Recommendations for In Vitro and In Vivo Testing of Magnetic Nanoparticle Hyperthermia Combined with Radiation Therapy

Magnetic nanoparticle (MNP)-mediated hyperthermia (MH) coupled with radiation therapy (RT) is a novel approach that has the potential to overcome various practical difficulties encountered in cancer treatment. In this work, we present recommendations for the in vitro and in vivo testing and application of the two treatment techniques. These recommendations were developed by the members of Working Group 3 of COST Action TD 1402: Multifunctional Nanoparticles for Magnetic Hyperthermia and Indirect Radiation Therapy ("Radiomag"). The purpose of the recommendations is not to provide definitive answers and directions but, rather, to outline those tests and considerations that a researcher must address in order to perform in vitro and in vivo studies. The recommendations are divided into 5 parts: (a) in vitro evaluation of MNPs; (b) in vitro evaluation of MNP-cell interactions; (c) in vivo evaluation of the MNPs; (d) MH combined with RT; and (e) pharmacokinetic studies of MNPs. Synthesis and characterization of the MNPs, as well as RT protocols, are beyond the scope of this work.

Assessment of research models for testing gene-environment interactions

Throughout the last century, possible effects of exposure to toxicants, nutrients or drugs were examined primarily by studies of groups or populations. Individual variation in responses was acknowledged but could not be analyzed due to lack of information or tools to analyze individual genetic make-ups and lifestyle factors such as diet and activity. The Human Genome, Haplotype Map, 1000Genomes, and Human Variome Projects are identifying and cataloging the variation found within humans. Advances in DNA sequencing technologies will soon permit the characterization of individual genomes in clinical and basic research studies, thus allowing associations to be made between an individual genotype and the response to a particular exposure. Such knowledge and tools have generated a significant challenge for scientists: to design and conduct research studies that account for individual genetic variation. However, before these studies are done in humans, they will be performed in various in vivo and in vitro models. The advantages and disadvantages of some of the model test systems that are being used or developed in relation to individual genetic make-up and responses to xenobiotics are discussed.

Screening for cytotoxicity in neuroblastoma cells. I. Dependence of growth inhibition on the presence of serum

The growth-inhibitory effects of a variety of potentially toxic compounds on neuroblastoma cells in defined, serum-free medium were compared with those in serum-containing medium. For 13 of 21 compounds tested, concentrations between 2 and 10(5) times higher were required for 50% inhibition of growth in serum-containing medium. The ranking of substances for their potency in inhibiting growth was thereby different in the two different culture conditions. The presence of bovine serum albumin (BSA) in the medium had similar effects as serum on the dose-response curves.

Comparison of the effects of metals on cellular injury and lipid peroxidation in isolated rat hepatocytes

Various mechanisms, including increases in lipid peroxidation, have been proposed to account for metal-induced cellular injury. By comparing several metals in the same cell population, it is possible to determine whether a correlation exists between ability to produce cell injury and ability to alter parameters pertaining to a particular mechanism. Of particular interest in this study was the relation between metal-induced cytotoxicity and increases in lipid peroxidation. The effects of Cr, Mn, Zn, Ni, Pb, Se, V, Fe, Cd, Hg, Cu, at final concentrations of 1-1000 microM, on the viability of isolated hepatocytes were therefore examined by assessing the loss of intracellular K+ and aspartate aminotransferase (AST). Simultaneously, the ability of the metals to induce lipid peroxidation, as measured by an increase in thiobarbituric acid (TBA) reactants, was assessed. Hg and Cu required the lowest concentration to produce cellular injury, while Cd produced less dramatic changes in cell viability and Fe at 1000 microM produced only a small decrease in intracellular K+. The largest absolute increases in lipid peroxidation were found in the presence of V, followed by Fe and Hg, with Cd and Se causing the smallest increase in TBA reactants. These observations suggest that the lipid peroxidation associated with Cd and Hg is not necessarily responsible for the loss of cell viability induced by these two metals.

Toxicology investigations with cell culture systems

This review concerns some of the cell culture systems that are most frequently used in toxicology investigations. In particular, it sets out to evaluate the effectiveness of these cell culture systems in assessing the toxic potential of chemicals. Metabolic studies and general and specific toxicology investigations are highlighted. Specific toxicology investigations relate to the effects of the tests substances on the highly specialized functions typical of the cell systems chosen. The general toxicology investigations include most of the other studies where differentiated or undifferentiated cells have been used to evaluate the effects of the tested substances on common basic biochemical processes essential for life. Lastly, we have attempted to focus attention on the most promising applications of cell cultures in toxicology studies for the near future and to identify those areas where further research is needed. Because of the several excellent reviews that already exist, we have decided not to consider cell cultures utilized in screening potential mutagens and carcinogens. We have also excluded investigations of drug therapeutic effects and action mechanisms of drugs.

Mitochondrial alterations produced by misonidazole: a study using Amoeba proteus as a single-cell model

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The systematic appraisal of cellular injury

From a study of the ultrastructural effects of numerous injuries agents on cultured kidney and liver cells, a check-list has been drawn up which summarizes all of the changes observed in subcellular components. The checklist resembles a multiple-choice test. Its use would permit greater standardization among workers reporting ultrastructural alterations observed in injured cells. It would also increase the objectivity with which cell injury can be assessed by electron microscopy. The checklist is suitable for use in computer-based programs designed to characterize types of cellular injury and for seeking correlations in ultrastructural changes arising from different forms of treatment.