Our strategy was to use a custom microarray platform developed for the axolotl (Huggins et al., 2012) to compare gene expression differences over the first week after injury between an injured tissue that will not form a limb (flank wound), an example of aborted limb regeneration (denervated limb), and a regenerating limb (Fig. 1A C).
Denervated limbs were chosen because they are an example of aborted limb regeneration – they present limb-specific gene expression patterns but do not generate a blastema.
We compared the results with available information on single muscle fibers from VL, taken as representative example of lower limb muscles.
We illustrate the above concept by using an example of vertebrate limb bud formation and elongation processes, the system with a long history of research (Wolpert et al., 1998).
This video shows a representative example of hind limb paralysis in a 6 week old TDP-43WTxQ331K mouse, displaying a severely stilted gait, and an inability to lift their pelvis from the ground.
When I got to the example of phantom-limb sensations, he perked up.
The Lower Limb Functional Index (LLFI) is another recent example of a lower limb regional PRO.
With three examples of upper limb fractures in children (distal radius, Salter–Harris Type II, displaced supracondylar fracture, and displaced fracture phalanx), I would like to explain how to reduce each of them.
For example, certain genetic or pharmacological perturbations can result in planarian worms with either two or no heads (Reddien and Sánchez Alvarado, 2004; Oviedo et al., 2010; Beane et al., 2011), while cutting and grafting experiments provide many examples of changes of limb morphology in insects and amphibians (Endo et al., 2000; Yakushiji et al., 2009).
An example of divergence is limb evolution in birds and bats where the forelimbs are selected for flight, whereas the hind limbs are selected for perching or walking (Young and Hallgrimsson 2005).
