Animals experimentation

Although, as indicated above, ethanol could promote the development of PHC by several mechanisms, no animal study has yet revealed an effect of chronic ethanol consumption on the post-initiation phase. Schwarz et al. (1983) administered diethylnitrosamine (3 mg/kg) to female Wistar rats and, after the animals had been allowed to recover from the toxic effects of the carcinogen, administered ethanol in the drinking water (10% w/v) for 16 weeks. This low dosage had no effect on the number or size of ATPase-deficient foci. 

Similar negative effects of ethanol on tumor development were reported by Teschke et al. (1982). They administered ethanol in a liquid diet (36% of total calories) to female Sprague-Dawley rats for 3 weeks. 

Other experiments, although not designed to distinguish initiation and post-initiation effects, also failed to demonstrate an effect of ethanol on liver hepatocarcinogenesis (Schmahl et al., 1965 Habs and Schmahl, 1981). 

Several retrospective cohort studies have shown a significant correlation between chronic consumption of ethanol and the development of hepatocellular carcinoma. In this review, several mechanisms by which ethanol could exert its effects have been considered. Ethanol itself does not appear to be carcinogenic or genotoxic, but it may modify either the ini- 

Second, the diets used in laboratory experiments generally provide nutrients at optimum levels for growth and reproduction, whereas it is known that ethanol causes depletion of certain nutrients more rapidly on marginal diets (Sato and Lieber, 1982 Ahmed and Russell, 1982). Thus, it may be advantageous to study the effects of ethanol consumed in combination with marginal diets. 

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Since the fundamental mcclumisms tliat cause toxic responses are not fully understood, toxicological findings are largely based on observations. Altliough some of the toxicological information relating to hmnans is based on human experience, tlie majority of this information is derived from animal experimentation. 

Animal experimentation has revealed inhaled concentrations that result in death following acute, intermediate, and chronic exposure. An LC50 value for acute exposure in rats was reported as 12,500 ppm for a 4-hour exposure (Siegel et al. 1971). Two out of 10 mice died after a 4-hour exposure to 6,400 ppm trichloroethylene (Kylin et al. 1962). Death was often caused by the central nervous system depression that... 

It is imperative, however, to understand the probabilistic nature of such experiments a promising profile on pharmacogenomic and toxicogenomic screens will enhance the likelihood of having selected an ultimately successful compound, and will achieve this goal quicker than conventional animal experimentation, but will do so only with a certain likelihood of success. The less reductionist approach of the animal experiment will still be needed. It is to be anticipated, however, that such approaches will constitute an important, time- and resource-saving first evaluation or screening step that will help to focus and reduce the number of animal experiments that will ultimately need to be conducted. 

Camacho-Ibanez R, Meckes-Lozoya M and Mellado-Campos V. 1983. The hypoglycemic effect of Opuntia streptacantha studied in different animal experimental models. J Ethnopharmacol 7 175-181. 

Animal experimental models of nickel-induced skin sensitivity are few and have been conducted only under very specialized conditions (USEPA 1986). Studies examining the mechanism of nickel contact sensitization and its extent in wildlife are needed (USPHS 1993). The importance of the surface properties and crystalline structure of nickel compounds in relation to their reactivity and protein-binding activities is well documented. It is therefore necessary to identify clearly the nickel compounds to which exposure occurs (Sunderman etal. 1984). Acute and chronic dermal and... 

Gad, S.C. (1989b). A tier testing strategy incorporating in vitro testing methods for pharmaceutical safety assessment. Flumane Innovations and Alternatives in Animal Experimentation 3 75-79. 

In practice, atmospheric pressure in most animal experimental environments usually varies only a few mm Hg, so little or no correction is required. 

Drew, R.T. and Laskin, S. (1973). Environmental inhalation chambers. In Methods of Animal Experimentation Vol. IV Academic Press, New York, pp. 1-41. 

There may be some role for animal experimentation here, if there is a suitable model, because it gives the chance to study the organism under intense pressure from commensals and the rising immune response. 

The experiment should be so designed and based on the results of animal experimentation... 

The use of microorganisms as a complementary tool in the study of drug metabolism is certainly becoming more popular. The examples cited above provide additional evidence of the utility of such systems as alternative in vitro models for investigating drug metabolism in humans. However, as mentioned above, no in vitro model could ever completely replace animal experimentation in medical research, and the predictive value of microbial systems, even if they frequently correlate with their animal counterpart, is questionable. Nevertheless, microorganisms can be used as a reliable and efficient alternative to small animals or... 

Uptake of inert gases in respiratory tract animal experimentation on, 281 improved methods of studying, 312-13 lung, 285-93... 

Diquat poisoning is much less common than paraquat poisoning, so that human reports and animal experimental data for diquat poisoning are less extensive than for paraquat. However, diquat has severe toxic effects on the central nervous system that are not typical of paraquat poisoning (Vanholder et al. 1981 Olson 1994). 

Johann Jakob Wepfer (1620-1695) was the first to verify by animal experimentation assertions about pharmacological or toxicological actions. 

Animal Use in the Life Sciences. Progress in the Reduction, Refinement and Replacement of Animal Experimentation. Amsterdam Elsevier, 2000 613-21. 

In Balls M, Van Zeller A-M, Haider M, eds. Proceedings of the Third World Congress on Alternatives and Animal Use in the Life Sciences. Progress in the Reduction, Refinement and Replacement of Animal Experimentation. Amsterdam Elsevier, 2000 783-91. 

In the United Kingdom, by the time of the adoption of the Directive, the authorities had already introduced legislation for the control of animal experimentation in the form of the Animal and Scientific Procedures Act 1986. Its content and coverage was already relatively comprehensive of the requirements set out under the Directive, and so relatively little needed to be done to bring the UK law in line with the European provisions. 

Medical research involving human subjects must conform to generally accepted scientific principles, be based on a thorough knowledge of the scientific literature, other relevant sources of information, and on adequate laboratory and, where appropriate, animal experimentation. 

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