The main focus of the research that makes up this thesis was to translate rodent behavioural assays to larval zebrafish for better time and resource management in biomedical research,... Show moreThe main focus of the research that makes up this thesis was to translate rodent behavioural assays to larval zebrafish for better time and resource management in biomedical research, pharmaceutical research and development. __The larval zebrafish is a useful model in toxicology and drug discovery. However, its predictivity is restricted by compound class. __Light-dark cycle plays an important role in the normal development of the zebrafish embryo, and abnormal lighting regimes during rearing can result in malformations. __The hyperactivity displayed by zebrafish larvae following the onset of sudden darkness is an intrinsic characteristic. Zebrafish larvae quickly habituate with repeated stimuli of onset of darkness with short interstimulus interval. __Zebrafish larvae are able to discriminate colours, and they show a preference for orange and green, but aversion towards red, yellow, blue and black. The larvae also show freezing behaviour in the complex environment which is attenuated with diazepam.. __Zebrafish larvae raised in an abnormal lighting regime changed some aspects of their colour preference, although orange and red remained as preferred and avoided colours respectively. __In short, the zebrafish larvae is a useful complementary animal model in behavioural research amenable to high-throughput screening of compounds and drug discovery Show less
In this thesis, four studies on children and adolescents with Down syndrome are described. The first study showed that the number of live births of children with Down syndrome in the Netherlands... Show moreIn this thesis, four studies on children and adolescents with Down syndrome are described. The first study showed that the number of live births of children with Down syndrome in the Netherlands remained stable over the period 1997-2007 on 14.6 per 10,000 births. Of these, 85% were live born. In the second study is observed that growth retardation in children with Down syndrome meanly occurs in three critical periods of growth, resulting in shorter final stature and smaller head circumference than the general Dutch population shows. Furthermore, Dutch children with Down syndrome have alarmingly high prevalence rates of overweight and obesity during childhood and adolescence. The third study showed that eight-year-old children with Down syndrome have an average developmental delay of four years, more often have emotional and behavioral problems, and have a less favorable health-related quality of life (HRQoL) compared with children from the general population. Children with Down syndrome and recurrent respiratory tract infections showed relatively more delayed development. In the fourth study, results showed that adolescents with Down syndrome remain dependent to a large degree and have serious difficulties in functioning socially. Additionally, results showed that serious problem behavior is highly prevalent in adolescents with Down syndrome. Show less
