availability = practical applicability?

Context:
Xenotransplantation—the use of animal organs, tissues or cells in humans—has increased in the past decade. Previous difficulties in helping a human host accept such transplants have been largely overcome because of the increasing availability of genetically modified pigs equipped with genes to protect them from the human immune response. Recent progress and the future potential of xenotransplantation is outlined in a Review by authors from the University of Pittsburgh, USA.
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