Chapter 7 Answers to Select Review Questions

1.  Name two examples of animal models of human disorders.

Examples include experiments on the use of insulin to treat diabetes in dogs and the testing of penicillin for safe use in guinea pigs. 

3.  List three characteristics of mice that make them suitable for the study of gene function in vivo.

Mice and humans are genetically similar.  Many human disorders are genetically based or have genes for which the corresponding protein products may respond to therapeutics and these genes are represented in the mouse genome.  Mice also exhibit characteristics suitable for the study of gene function in vivo such as: 

Mammalian phenotype
Short gestation period
Reasonably short life cycle

6.  Why is the HPRT locus an ideal candidate gene for proving site-specific gene targeting methods?

As an x-linked enzyme, mutation of this locus results in a functional null that can be selected and enriched for in tissue culture.

9.  What is the major disadvantage to performing HTS on primary cells?

The major disadvantage to this approach is scarcity.

16.  What was the data output for Doug Foltz's assay to identify therapeutics for glioblastoma?

Potency of candidate molecules was assessed by the generation of dose response curves and calculation of the IC50, which is defined as half of the maximum proliferation inhibitory concentration of the compound.

20.  What are the three main impacts stem cells may have regarding toxicity testing strategies?

There are three main impacts stem cells may have with respect to toxicity testing:

1.  Developmental environmental toxicity

2. "Adult" environmental toxicity

3.  Therapeutic toxicity

23.  How did  Kyle Kolaja's group assess changes in cardiomyocyte QT intervals in response to exposure to different compounds?

His group measured impedance, which is the measurement of the opposition a circuit imposes on current when a voltage is applied, across the electrodes which provides an indirect assessment of both cell number and cell interaction with the interface of the dish.  This allowed for the detection of the physical movement of contracting cardiomyocytes differentiated from iPS cell sources (iPSC-CMs).