Quinidine-induced decrease of intracellular esterase activity in a hepatoma cell line.

O T Markovic; D S Young; N S Markovic

Home/Archive/PubMed

PubMed · 2832100

Quinidine-induced decrease of intracellular esterase activity in a hepatoma cell line.

O T Markovic·D S Young·N S Markovic

View original source ↗Export metadata ↓

Abstract

Using image-analyzing equipment, we measured the effect of quinidine on the activity of naphthol AS-D chloroacetate esterase, alpha-naphthyl butyrate esterase, alpha-naphthyl acetate esterase, and acid phosphatase in individual cells of a human Hep G2 hepatoma cell line. The impact of the drug on the morphology of the cells was also observed. Depending on the concentration of quinidine applied, various changes occurred, the most extreme being cell death. However, at some drug concentrations that did not appear to affect visible cell structures, the activity of the esterases was decreased. This lessened enzyme activity did not seem to be related to the enzymes leaking from the cells, because the activity of acid phosphatase was unaffected. Inhibition of the esterase activity was related to the interval of exposure to quinidine in the perfusing medium and to the concentration of the drug. We consider the system described here to be a potential replacement for experiments with animals in the study of hepatotoxicity.

Explore related subjects

Animal Testing Alternatives Carboxylic Ester Hydrolases Carcinoma, Hepatocellular Cell Survival Chemical and Drug Induced Liver Injury Humans Kinetics Liver Neoplasms Naphthol AS D Esterase Quinidine Tumor Cells, Cultured Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

O T Markovic, D S Young, N S Markovic. 1988. Quinidine-induced decrease of intracellular esterase activity in a hepatoma cell line.. https://pubmed.ncbi.nlm.nih.gov/2832100/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Preclinical cardio-safety assessment of torsadogenic risk and alternative methods to animal experimentation: the inseparable twins.

The last decade has been marked by the withdrawal from the market of several medicines whose use in patients has been associated with the development of torsade de pointes (TdP), a potentially life-threatening polymorphic tachycardia. In a few cases, TdP can degenerate into ventricular fibrillation and lead to sudden death, thus constituting a real problem of public health. The recently finalized ICH S7B guideline defines the prolongation of the QT interval on the electrocardiogram as the best biomarker for predicting the torsadogenic risk of a given compound. However, a growing body of evidence suggests that drugs' torsadogenic potential may not necessarily be proportional to their ability to prolong the QT interval. It is a dynamic combination of multiple predisposing factors and components rather than a single particular event that can trigger this particular tachycardia. Following recommendations of the guideline, pharmaceutical companies have intensively implemented methodologies to assess the possible risk of QT prolongation and TdP in humans. The main problem in cardiac safety pharmacology is how best to combine the capabilities of different methodologies with their strengths and limitations in order to detect the potential of one molecular entity to induce a lethal arrhythmia of very low clinical incidence. This publication will review the current methodologies, focusing on the alternative methods to animal experimentation, including an overview of cardiac modeling.

Animal Testing Alternatives↗

PubMed2007

Genetic toxicity assessment: employing the best science for human safety evaluation part III: the comet assay as an alternative to in vitro clastogenicity tests for early drug candidate selection.

Early screening of drug candidates for genotoxicity typically includes an analysis for mutagenicity in bacteria and for clastogenicity in cultured mammalian cells. In addition, in recent years, an early assessment of photogenotoxicity potential has become increasingly important. Also, for screening purposes, expert computer systems can be used to identify structural alerts. In cases where structural alerts are identified, mutagenicity testing limited to bacteria can be conducted. The sequence of computer-aided analysis and limited testing using bacteria allows for screening a comparatively large number of drug candidates. In contrast, considerably more resources, in terms of supplies, technical time, and the amount of a test substance needed, are required when screening for clastogenic activity in mammalian cells. In addition, the relatively large percentage of false positive results for rodent carcinogenicity associated with clastogenicity assays is of considerable concern. As a consequence, mammalian cell-based alternatives to clastogenicity assays are needed for early screening of mammalian genotoxicity. The comet assay is a relatively fast, simple, and sensitive technique for the analysis of DNA damage in mammalian cells. This assay seems especially useful for screening purposes because false positives associated with excessive toxicity appear to occur less frequently, only relatively small amounts of a test compound are needed, and certain steps of the test procedure can be automated. Therefore, the in vitro comet assay is proposed as an alternative to cytogenetic assays in early genotoxicity/photogenotoxicity screening of drug candidates.

Animal Testing Alternatives↗

PubMed2007

Development and characterization of a canine skin equivalent.

The development of a complex cellular model, which incorporates the basic cell components of the dog skin, would be a useful tool to investigate the biology and pathology of canine skin and also to replace animal testing partially. The aim of the present study was to develop and characterize a canine skin equivalent. Epidermal keratinocytes and dermal fibroblasts were freshly isolated from skin biopsies from healthy dogs. Fibroblasts were embedded into a bio-matrix from collagen type I matrix protein; this built the scaffold where the keratinocytes were seeded, at air exposed conditions. At 3, 7, 15 and 21 days of culture in special growth media, skin equivalents were analysed by histological, immunohistochemical and electron microscopical techniques. At 15 days, keratinocytes underwent differentiation to a multilayer epidermis with stratum basal, stratum spinosum, stratum granulosum and stratum corneum. Expression of epidermal cytokeratins in keratinocytes was detected by immunhistochemistry, and followed the same pattern than in the normal canine epidermis. Fibroblasts from the skin equivalent expressed vimentin as dermal fibroblasts do. A basement membrane (BM) was observed underneath the epidermis; ultrastructurally, it was similar to the normal canine BM and collagen IV and laminin 5 were detected immunohistochemically as major components of this structure. Skin equivalents developed from canine cutaneous cells presented a similar morphological structure than healthy canine skin. Moreover, the immunohistochemical analysis revealed the expression of the major markers of the epidermis (keratins), dermis (vimentin) and BM (collagen type IV, laminin 5).

Animal Testing Alternatives↗