Zebrafish embryos as an alternative to animal experiments--a commentary on the definition of the onset of protected life stages in animal welfare regulations.

Worldwide, the zebrafish has become a popular model for biomedical research and (eco)toxicology. Particularly the use of embryos is receiving increasing attention, since they are considered as replacement method for animal experiments. Zebrafish embryos allow the analysis of multiple endpoints ranging from acute and developmental toxicity determination to complex functional genetic and physiological analysis.

Principles and perspectives.

Background, Aim And Scope: With respect to the enormous increase of chemical production in the last decades and the tens of thousands of individual chemicals on the market, the permanent improvement of chemical management is a permanent target to achieve the goals of sustainable consumption and production set by the WSSD in Johannesburg 2002.

Main Features: Several approaches exist to describe sustainability of chemistry. However, commonly agreed criteria are still missing.

The angle between the Frankfort horizontal and the sella-nasion line. Changes in porion and orbitale position during growth.

Aim: The starting point of this study was the statement made in the literature that the angle between the two reference planes Frankfort horizontal (FH) and sella-nasion line (SN) changes relatively little during growth. The growth-induced relocation of the orbitale (Or; anterior reference point of the FH) in relation to SN is known from implant studies, whereas the relocation of the porion (Po; posterior reference point of the FH) has been the subject of only little research. The present study was aimed at analyzing the factors contributing to the almost constant angle between FH and SN.