Developmental propensity

In summary, the life cycle of S. ratti contains a switch between two developmental routes. The developmental propensity phenotype varies between different isofemale lines and this can be altered by artificial selection. This shows that there is diversity for this trait both within and between parasite... 

Considering the fact that an increase in the percentage of wake parallels the decrease of REM sleep, the wake/REM (W/R) ratio might be an important index to describe the developmental levels in altricial mammals. This ratio is about 0.4 (28%/72%) in the first 10 days of life in the rat (4), dramatically increases to 1.77 at PN 21, 3.99 at PN 26 (9), and 8.1 in adulthood (calculated from Ref. 152). This ratio is 1.0 in the human newborn and is 2.6,10.3, and 11 at PN 1, PN 14-18, and adult, respectively (calculated from Ref. 12). The developmental features of sleep-wake states suggest that the strong REM sleep propensity in neonates is progressively suppressed or that a REM sleep inhibitory process is immature in neonatal rats. 

Sheen S, Banfield N, Addy M The propensity of individual saliva to cause extrinsic staining in vitro — a developmental method. J Dent 2001 29 99—102. 

The techniques described in this chapter can be of use to the optimization of lead compounds during drug discovery processes. However, the link between drug-protein adduct formation and toxicity has not been well defined. Additional considerations should be taken, such as therapeutic area and clinical doses. It has been suggested that a 10 mg daily dose rarely results in drug-related adverse effects (Uetrecht, 1999). Thus, the propensity of bioactivation should only be considered as one of the factors in the selection of developmental drug candidates. 

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