Biological barriers, typically, represented by epithelial tissues are the main hindrance against uncontrolled uptake of a variety of substances. However, the delivery across a biological barrier is a crucial factor in the development of drugs. As the permeability of macromolecular ...

Transfer of exogenous material into the cytosol of cells is one of the main challenges in drug delivery. We present a novel physical approach for efficient incorporation of macromolecules into living cells, based on exposing them to a train of unipolar electric field pulses, possessing much l ...

To avoid long-double-stranded-RNA-dependent interferon response, short-interfering RNAs (siRNAs) are widely used for RNA interference (RNAi) in mammalian cells. siRNA-based RNAi, however, may not be readily available for the large-scale gene silencing essential for system ...

Isolated through combinatorial libraries by an iterative in vitro selection process, small single-stranded nucleic acid compounds, named aptamers, have been developed as high-affinity ligands for a variety of targets, ranging from small chemical compounds to large proteins. In t ...

This chapter describes a method for establishing short-term expiant cultures of esophageal mucosa. Adverse effects produced by exposure to radiation or test compounds can be detected as an inhibition of cell outgrowth.

The safety assessment of new chemicals and pharmaceuticals and the incorporation of these data into a human risk assessment package requires a large number of expensive, regulated tests in animal species including, in some cases, nonhuman primates (1–3).

The reader is referred to the previous chapter in which the background and rationale for monitoring hypothalamic function in vitro is discussed.

Together, the hypothalamus and the pituitary gland form the functional unit called the neuroendocrine system. For the purposes of introducing this system, therefore, the two will be considered together, although the methods for assessing their function will be considered separate ...

The technique described in this chapter enables the culturing of thyroid cells without loss of differentiation and medium change. It is potentially useful for the long-term study of drug effects on the thyroid gland. Human thyroid cells obtained during surgery can be maintained in culture f ...

Cultured astrocytes provide a valuable and important system for predictive testing and mechanistic analysis of neurotoxic compounds. The culture procedures allow relatively rapid assessment of different chemicals or their metabolites over a range of concentrations, using c ...

In this test, kidney-derived cells are cultured in the presence of test compounds whose cytotoxicity is then determined by the Neutral Red method, and serves as an indicator of potential nephrotoxicity (1). Healthy LLC-RK1 cells (an established cell line, ATCC CCL) maintained in culture cont ...

The development of in vitro models that preserve the functional characteristics of the normal thyroid gland has been a challenging objective of recent experimental thyroidology. A major aim of such endeavors has been to facilitate the development of simple, reliable, reproducible te ...

Macrophage cells in culture may be exposed to particulate matter, and resultant effects on cell viability are determined by vital dye exclusion and enzyme leakage assays.

The well-documented existence of interspecies differences in the responses elicited by exposure to chemical agents (1–3) represents the main difficulty in the extrapolation to humans of the results of toxicity studies carried out in laboratory animals or in in vitro systems employing ...

This test is designed to detect irreversible toxic effects on both cell growth and survival, by the evaluation of colony-forming (CF) efficiency, in hepatoma cell lines derived from humans, rat, and mouse. The liver is a major target organ for the cytotoxicity of many xenobiotics. It has been sugges ...

The model cavity method enables the in vitro cytotoxicity testing of dental restorative materials that may then be related to dental toxicity likely to occur in vivo.

The cytotoxic effect of chemicals on cells in culture is measured by the change in total cell protein (Kenacid Blue R dye binding method). Healthy 3T3-L1 cells (an established cell-line, ATCC CCL92.1), when maintained in culture continuously divide and multiply over time. The basis of this test is t ...

The membrane theory of toxicity (1) emanates from the fact that the plasma membrane is the first barrier met by a toxic agent on reaching the cell, and was first advanced to explain the toxic effects of heavy metals. The vital regulatory mechanisms inherent in the plasma membrane and its chemical compo ...

The Allium test provides a rapid screening procedure for chemicals, pollutants, contaminants, and so on that may represent environmental hazards. Root growth inhibition and adverse effects on chromosomes provide an indication of likely toxicity.

The MTT calorimetric assay determines the ability of viable cells to convert a soluble tetrazolium salt (MTT) into an insoluble formazan precipitate. Tetrazolium salts accept electrons from oxidized substrates or appropriate enzymes, such as NADH and NADPH. In particular, MTT is redu ...