[Xenotransplantation and animal welfare]

The problems of feasibility and public acceptance of using animals as foreign donors for organ transplants (xenotransplantation) are discussed from an animal protection point of view. It is proposed that a transparent information and a transdisciplinary composition of the members of decisive bodies is ensured to incorporate the current distrust towards xenotransplantation of a large part of the population. This strategy could lead to a consensus for or against such animal use of the whole society before it is technically possible and therefore irrevocable facts are created.

[In search of an in vitro model for neuroteratology]

In vitro models for neuroteratology are briefly reviewed with emphasis on embryonic brain cells in vitro (in Petri dishes and as aggregate cultures under constant gyratory movement). A new model on randomly aggregated cells from embryonic chick brain (embryonic day 7) to detect potential toxic insults is presented. The same cell population is observed on Petri dishes and as aggregate cultures under various treatment schedules. Cell development and differentiation of the various cell types are monitored by qualitative PAP-staining of specific antibodies against glial fibrillary acidic protein (GFAP, marking type-2 astrocytes), 68kD-neurofilament (marking nerve cells) and tyrosine hydroxylase, as well as quantitative ELISA using cytotoxicity end-points (neutral red uptake). Drugs and other chemicals are selected on the basis of their known interference with behavior and with the dopaminergic system (neurotoxic and neuromodulatory drugs) in order to evaluate the usefulness of a stable and fully differentiating brain tissue model for screening a neuroteratogenic activity.

[Possibilities of cell culture methods and alternatives to animal tests in toxicology]

A current basic shift in the ethical, scientific and commercial engagement for alternatives to animal experimentation is described which is a prerequisite for their stronger use in practice. A review on the various alternatives is given with emphasis on cell culture methods and toxicology. The most promising alternatives are prospectively summarized and some known limits of in vitro systems are discussed in comparison with the value of results from animal experimentation and in the context of safety evaluations in toxicology.

Effects of the "sexcombless" chromosome (In(1)sx) on males and females ofDrosophila melanogaster.

The chromosome which carries the mutationsexcombless (In(1)sx) affects males and females ofD. melanogaster. In the male foreleg basitarsi the number of sexcomb teeth is dramatically reduced from 10 to 0.7 and the number of transverse rows of bristles is increased from 6 to 8. Females homozygous forIn(1)sx show a normal bristle pattern in the foreleg basitarsus. The genital disc derivatives of both male and femaleIn(1)sx flies are strongly affected. While the external genitalia show a duplicated or a reduced bristle pattern, the internal genitalia are mostly absent. However, the sexually dimorphic tergites and sternites of the abdomen remain unaffected. The male-specific effect on the basitarsus and the general effects on the genital disc derivatives are proposed to represent two different phenotypic effects ofIn(1)sx which may derive from mutations at different gene loci in the inverted chromosome.