Vitamin D receptors are present in nearly every tissue in the human body.

FORBES: Vitamin D: Still More Questions Than Answers

As the source of every cell, tissue and organ in the body, their medical application has the potential to repair damaged tissue, regrow internal organs and cure currently incurable diseases like cystic fibrosis, Alzheimer's and Parkinson's.

CNN: You, again: Are we getting closer to cloning humans?

"Every time I hear Danny Boy I reach for a tissue because it makes me so sad, " he added.

BBC: Plan to pipe out Danny Boy in Limavady

"Advances in medicine are being made every day in different areas, whether it's tissue transplantation or tissue regeneration, " he said.

CNN: Iraq vet undergoes successful double-arm transplant