In Vitro Toxicology and the Test Guidelines

1996 ◽  
Vol 24 (3) ◽  
pp. 435-438
Author(s):  
Kimmo Louekari
Keyword(s):  
Cost Effective ◽  
Test Methods ◽  
In Vitro Tests ◽  
In Vitro Test ◽  
In Vitro Methods ◽  
Effective Manner ◽  
Genotoxic Carcinogens ◽  
Vitro Test

Ethical, economical and scientific considerations should encourage the development of alternative and in vitro test methods. Before their adoption, in vitro methods need to be validated and scientifically justified. Demand for rigorous validation schemes for in vitro tests must be emphasised, even more than in the case of in vivo tests. The OECD has adopted in vitro guidelines for testing genotoxicity; several endpoints and mechanisms can be studied in a cost-effective manner in vitro. Similar advantages could be afforded if acute irritation and corrosion, as well as the non-genotoxic carcinogenic effects of chemicals, could be studied in vitro. Evaluation of the validation status of various methods used to study non-genotoxic carcinogens was begun by the Nordic Working Group on In Vitro Methods for Non-genotoxic Mechanisms in 1996. In some established OECD test guidelines (for example, the dermal irritation/corrosion test), there is already room for the application of in vitro methods which have not been formally validated. In January 1996, the OECD Workshop on Harmonisation of Validation and Acceptance Criteria for Alternative Toxicological Test Methods set the basis for internationally acceptable principles to be followed in the validation of in vitro test methods.

In Vitro Toxicology Methods in Risk Assessment

1996 ◽  
Vol 24 (3) ◽  
pp. 325-331
Author(s):  
Iain F. H. Purchase
Keyword(s):  
Risk Assessment ◽  
Hazard Assessment ◽  
Human Health Risk ◽  
In Vitro Test ◽  
In Vitro Methods ◽  
New Concepts ◽  
Vitro Test

The title of this paper is challenging, because the question of how in vitro methods and results contribute to human health risk assessment is rarely considered. The process of risk assessment usually begins with hazard assessment, which provides a description of the inherent toxicological properties of the chemical. The next step is to assess the relevance of this to humans, i.e. the human hazard assessment. Finally, information on exposure is examined, and risk can then be assessed. In vitro methods have a limited, but important, role to play in risk assessment. The results can be used for classification and labelling; these are methods of controlling exposure, analogous to risk assessment, but without considering exposure. The Ames Salmonella test is the only in vitro method which is incorporated into regulations and used widely. Data from this test can, at best, lead to classification of a chemical with regard to genotoxicity, but cannot be used for classification and labelling on their own. Several in vitro test systems which assess the topical irritancy and corrosivity of chemicals have been reasonably well validated, and the results from these tests can be used for classification. The future development of in vitro methods is likely to be slow, as it depends on the development of new concepts and ideas. The in vivo methods which currently have reasonably developed in vitro alternatives will be the easiest to replace. The remaining in vivo methods, which provide toxicological information from repeated chronic dosing, with varied endpoints and by mechanisms which are not understood, will be more difficult to replace.

Animal Models and Alternatives in the Quality Control of Vaccines: Are In Vitro Methods or In Vivo Methods the Scientific Equivalent of the Emperor's New Clothes?

1995 ◽  
Vol 23 (1) ◽  
pp. 61-73
Author(s):  
Coenraad Hendriksen ◽  
Johan van der Gun
Keyword(s):  
Quality Control ◽  
Test Methods ◽  
In Vitro Test ◽  
Large Numbers ◽  
Alternative Approach ◽  
Inactivated Vaccines ◽  
Vitro Test

In the quality control of vaccine batches, the potency testing of inactivated vaccines is one of the areas requiring very large numbers of animals, which usually suffer significant distress as a result of the experimental procedures employed. This article deals with the potency testing of diphtheria and tetanus toxoids, two vaccines which are used extensively throughout the world. The relevance of the potency test prescribed by the European Pharmacopoeia monographs is questioned. The validity of the potency test as a model for the human response, the ability of the test to be standardised, and the relevance of the test in relation to the quality of the product are discussed. It is concluded that the potency test has only limited predictive value for the antitoxin responses to be expected in recipients of these toxoids. An alternative approach for estimating the potency of toxoid batches is discussed, in which a distinction is made between estimation of the immunogenic potency of the first few batches obtained from a seed lot and monitoring the consistency of the quality of subsequent batches. The use of animals is limited to the first few batches. Monitoring the consistency of the quality of subsequent batches is based on in vitro test methods. Factors which hamper the introduction and acceptance of the alternative approach are considered. Finally, proposals are made for replacement, reduction and/or refinement (the Three Rs) in the use of animals in the routine potency testing of toxoids.

Comparison of methods for measurement of the pressure exerted by knitted fabrics

2016 ◽  
Vol 87 (17) ◽  
pp. 2117-2126 ◽  
Author(s):  
Małgorzata Cieślak ◽  
Agnieszka Karaszewska ◽  
Ewa Gromadzińska ◽  
Izabela Jasińska ◽  
Irena Kamińska
Keyword(s):  
In Vitro Tests ◽  
Knitted Fabric ◽  
In Vitro Test ◽  
Knitted Fabrics ◽  
Weft Knitted Fabric ◽  
In Vivo Tests ◽  
Vitro Test ◽  
Warp Knitted Fabric

The article presents the results of measurements of pressure exerted by two model knitted products – bands with different structure (WI jersey weft-knitted fabric and WII openwork warp-knitted fabric). The tests were carried out with using the I-Scan system (in vivo and in vitro tests) and the STM 579 device (in vitro test). A comparative analysis of the in vivo and in vitro results for the I-Scan method and in vitro results for the I-Scan and STM 579 method was performed. It was found that the pressure values are lower for openwork warp-knitted fabric than for jersey weft-knitted fabric both in the case of the in vitro and in vivo tests, and the values of pressure for the same band are higher in the case of the in vitro tests.

scholarly journals Interlaboratory studies on in vitro test methods for estimating in vivo resorption of calcium phosphate ceramics

2015 ◽  
Vol 25 ◽  
pp. 347-355 ◽  
Author(s):  
Atsuo Ito ◽  
Yu Sogo ◽  
Atsushi Yamazaki ◽  
Mamoru Aizawa ◽  
Akiyoshi Osaka ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Test Methods ◽  
In Vitro Test ◽  
Calcium Phosphate Ceramics ◽  
Interlaboratory Studies ◽  
Vitro Test

In Vitro Toxicity Testing: Purpose, Validation and Strategy

1990 ◽  
Vol 18 (1_part_1) ◽  
pp. 11-18 ◽  
Author(s):  
Oliver P. Flint
Keyword(s):  
Cell Function ◽  
Toxicity Testing ◽  
In Vitro Toxicity ◽  
In Vitro Tests ◽  
In Vitro Test ◽  
Vitro Test ◽  
Basal Cytotoxicity ◽  
Biological Endpoint

The fullest potential for in vitro evaluation of toxicity will be realised in the context of the process of assessing the risk of human toxicity. This article is an attempt to clarify what contributions can be made by in vitro tests and what types of in vitro test can best be used. In vitro tests are clarified according to the type of biological endpoint evaluated, first into tests for general (‘basal’) cytotoxicity and, secondly, into tests for differentiated cell function. The role of each type of test is analysed and it is suggested that tests for general cytotoxicity, as opposed to differentiated function, are difficult to interpret in terms of in vivo toxicity. A general approach to evaluating in vitro tests is described, and a strategy for using these tests is proposed.

Lack of Influence of Povidone-Iodine on Tests of Thyroid Function

1978 ◽  
Vol 6 (5) ◽  
pp. 406-408 ◽  
Author(s):  
D P Lividas ◽  
G D Piperingos ◽  
J Sfontouris ◽  
D A Koutras
Keyword(s):  
Thyroid Function ◽  
Povidone Iodine ◽  
Test Methods ◽  
Thyroid Function Tests ◽  
In Vitro Test ◽  
External Application ◽  
Vitro Test ◽  
Antiseptic Agent

The external application of povidone-iodine, an antiseptic agent, was tested for its influence on thyroid function. Previous workers have described some in vitro changes in thyroid function tests following its use. In the present study topical application of povidone-iodine did not affect thyroid function as measured some days later using both in vivo and radio-active iodine in vitro test methods, despite the fact that the latter are notorious for being influenced by exogenous iodine.

The Application of in Vitro Models to Research on Demineralization and Remineralization of the Teeth

1995 ◽  
Vol 9 (3) ◽  
pp. 175-193 ◽  
Author(s):  
D.J. White
Keyword(s):  
Analytical Techniques ◽  
Test Methods ◽  
In Vitro Models ◽  
In Vitro Tests ◽  
In Vitro Testing ◽  
In Vitro Test ◽  
Dental Tissues ◽  
Testing Protocols

Progress in in vivo and in situ experimentation has led many researchers to speculate as to the relevance and importance of in vitro testing protocols in caries research. A Medline/Biosis search for the present review revealed well over 300 citations (since 1989) documenting in vitro tests associated with caries research on mineralization and fluoride reactivity. The present survey documents these recent applications of in vitro test methods in both mechanistic and 'profile'* caries research. In mechanistic studies, in vitro protocols over the past five years have made possible detailed studies of dynamics occurring in mineral loss and gain from dental tissues and the reaction dynamics associated with fluoride anticaries activity. Similarly, in profile applications, in vitro protocols make possible the inexpensive and rapid-yet sensitive-assessment of F anticaries efficacy within fluoride-active systems, and these tests represent a key component of product activity confirmation. The ability to carry out single variable experiments under highly controlled conditions remains a key advantage in in vitro experimentation, and will likely drive even further utilization, as advances continue in physical-chemical and analytical techniques for substrate analysis in these protocols. Despite their advantages, in vitro testing protocols have significant limitations, most particularly related to their inability to simulate the complex biological processes involved in caries.

Development and Evaluation of a Novel Artificial Catheter-Deliverable Prosthetic Heart Valve and Method for in Vitro Testing

2009 ◽  
Vol 32 (5) ◽  
pp. 262-271 ◽  
Author(s):  
Thomase Claiborne ◽  
Danny Bluestein ◽  
Richard T. Schoephoerster
Keyword(s):  
Heart Valve ◽  
State Of The Art ◽  
Prosthetic Heart Valve ◽  
Test Methods ◽  
In Vitro Testing ◽  
In Vitro Test ◽  
Vitro Test ◽  
Percutaneous Heart Valve

Background This work presents a novel artificial prosthetic heart valve designed to be catheter or percutaneously deliverable, and a method for in vitro testing of the device. The device is intended to create superior characteristics in comparison to tissue-based percutaneous valves. Methods The percutaneous heart valve (PHV) was constructed from state-of-the-art polymers, metals and fabrics. It was tested hydrodynamically using a modified left heart simulator (LHS) and statically using a tensile testing device. Results The PHV exhibited a mean transvalvular pressure gradient of less than 15 mmHg and a mean regurgitant fraction of less than 5 percent. It also demonstrated a resistance to migration of up to 6 N and a resistance to crushing of up to 25 N at a diameter of 19 mm. The PHV was crimpable to less than 24 F and was delivered into the operating LHS via a 24 F catheter. Conclusion An artificial PHV was designed and optimized, and an in vitro methodology was developed for testing the valve. The artificial PHV compared favorably to existing tissue-based PHVs. The in vitro test methods proved to be reliable and reproducible. The PHV design proved the feasibility of an artificial alternative to tissue based PHVs, which in their traditional open-heart implantable form are known to have limited in vivo durability.

Cytotoxicity of Biomaterials — Basic Mechanisms and In Vitro Test Methods: A Review

1995 ◽  
Vol 23 (6) ◽  
pp. 790-799 ◽  
Author(s):  
Thomas Groth ◽  
Peter Falck ◽  
Rainer-Reginald Miethke
Keyword(s):  
Cellular Proliferation ◽  
Test Methods ◽  
In Vitro Test ◽  
Clinical Use ◽  
Primary Cells ◽  
Cellular Functions ◽  
In Vitro Methods ◽  
Toxic Agents ◽  
Vitro Test

Biocompatibility is one of the main prerequisites for the clinical use of biomaterials. Central to the testing of biocompatibility is the estimation of cytotoxicity, which can be assessed in vitro by using a variety of different target primary cells or cell lines. The influence of toxic agents derived from biomaterials on cellular functions and cell viability can be characterised by reductions in cell adhesion, alterations in cellular morphology, reduced cellular proliferation, and cell death, demonstrated by an absence of metabolic activity, structural disintegration and cell lysis. A brief review of the basic mechanisms of cytotoxicity and the use of different in vitro methods for testing the cytotoxicity of biomaterials is presented.

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