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The influence of strain on demand functions for water in rats (Rattus Norvegicus).
by Dorte Bratbo Sørensen, Jan Ladewig & Lartey Godwin Lawson

Demand functions generated by operant conditioning techniques are used to assess animal priorities. In an operant system, the animal works to obtain a certain reinforcer, which enables the animal to perform a certain behaviour. The more motivated the animal is to perform this behaviour, the harder it will work to gain access to the reinforcer. It is important, however, to realise that a large number of factors may influence the demand function. To evaluate the impact of strain differences in rats on the demand function, two inbred rat strains worked for three different kinds of water in a closed economy. In Long Evans rats it was found that the demand for saccharine sweetened water and for acidified (HCl) water was the same, whereas the slope of the demand function for distilled water was significantly different from the other two. Wistar Kyoto rats showed the same demand for saccharine water and distilled water, although the total intake of saccharine water was significantly higher. The demand for acidified water was significantly different form the other two. The fact that there are strain differences when it comes to an essential reinforcer such as water in a closed economy, shows the necessity of considering strain differences when demand is evaluated in animals.

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Rodent models of intrauterine growth restriction.
by Camilla T. Haugaard and Michael K. Bauer

A number of IUGR models in rodents have been reviewed in this paper. These models make it possible to investigate different phenotypes of IUGR in rodents, which more or less resemble the human phenotypes, such as differential growth restriction, alteration in liver, kidney and placenta growth, delayed catch-up growth, and different aspects of syndrome X, such as elevated blood pressure, hyperinsulimia, insulin resistance, and dyslipidemia. These rodent models permit detailed studies of many aspects of IUGR, which are inaccessible through direct study of human pregnancy. However, necessary caution must be used when extrapolating from rodent models of IUGR to the growth restricted human infant. The rat for example has a relatively short gestation, and many important developmental events occur postnatally in rats that are part of fetal development in humans. This is one of the reasons why some investigators use the guinea pig, which also gives birth to a more developed fetus. Nevertheless, the existing animal models have already given valuable insights into IUGR in man, and are currently the only workable instrument to increase our knowledge.

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Development and validation of ELISAs for monitoring bacterial and parasitic infections in laboratory rodents and rabbits.
by R.Boot

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The need for defined diets and refined feeding methods
by Merel Ritskes-Hoitinga

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En reseberättelse från Eva Lindqvist, Lars Wass stipendiat år 2000

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Meet a Research Group: Diabetes Research Group, Bartholin Instituttet, Kommunehospitalet, Copenhagen, Denmark

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Meet another Member Association of FELASA: AISAL

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Meetings

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Meet a Company: Tapvei

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Index to Scandinavian Journal of Laboratory Animal Science 2000 vol. 27