Adult phenotype

There is no information regarding the metabolism of 3,3 -dichlorobenzidine in children. However, N-acetylation (as discussed above) in humans is likely done by one of two families of N-acetyltransferases. One of these families, NAT2, is developmentally regulated (Leeder and Kearns 1997). Some enzyme activity can be detected in the fetus by the end of the first trimester. Almost all infants exhibit the slow acetylator phenotype between birth and 2 months of age. The adult phenotype distribution is reached by the age of 4-6 months, whereas adult activity is found by approximately 1-3 years of age. Also, UDP-glucuronosyltransferase, responsible for the formation of glucuronide conjugates, seems to achieve adult activity by 6-18 months of age (Leeder and Kearns 1997). These data suggest that metabolism of 3,3 -dichlorobenzidine by infants will differ from that in adults in extent, rate, or both. 

Vandenbergh, J. G. and Hotchkiss, A. K. (2001). Interfetal communication and adult phenotype in mice. In Chemical Signals in Vertebrates, vol. 9, ed. A. Marchlewska-Koj, J. J. Lepri and D. Miiller-Schwarze, pp. 183-187. New York Kluwer Academic/Plenum. Vandenbergh, J. G., Whitsett, J. M., and Lombardi, J. L. (1975). Partial isolation of a pheromone accelerating puberty in female mice.Journal ofReproduction andEertility 43, 515-523. 

Some fetal activity by 16 weeks gestation. Poor activity between birth and 2 months of age. Adult phenotype distribution reached by 4-6 months with adult activity reached by 1-3 years. Fetal levels approximately 30% of adult values. In newborns, activity is approximately 50% higher than adults with phenotype distribution which approximates adults. Exception is Korean children where adult activity is seen by 7-9 years of age. 

Weller A, Leguisamo AC, Towns L, Ramboz S, Bagiella E, Hofer M, Hen R, Brunner D. Maternal effects in infant and adult phenotypes of 5HT1A and 5HT1B receptor knockout mice. Dev. Psychobiol. 2003 42 194-205. 

Classical global knockouts may have a developmental or lethal phenotype and thus preclude the analysis of the phenotypic consequences of the lack of a gene in specific tissues in adult animals. With the development of the cre/loxP and flp/FRT systems, it has become possible to excise defined DNA fragments from the genome of specified cells. Cre and Flp are bacterial and yeast recombinases, respectively, which recognize loxP and FRT sequences, respectively. The most common... 

Rosacea is a chronic disorder affecting the central parts of the face, characterized by flushing, persistent erythema and teleangectasia. Inflammatory papules and pustules can develop within the areas of erythema. Rosacea typically occurs in adults with fair skin and light eye and hair color. In contrast to acne, rosacea is not typically follicular in nature and comedones and seborrhea are usually absent. Pyoderma fa-dale is deemed to be an explosive form of rosacea, often occurring in young women with a phenotype typical of rosacea patients, often in the context of stress (Fig. 11.16). 

Edgar Some of the Minutes have been reported to give small cell phenotypes in adults. We have looked at a number in discs before the cells differentiate, and we have not seen any effects here. 

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