The laboratories have initiated Phase 1 clinical trials for the use of human pluripotent embryonic stem cells to treat paralyzed patients following spinal cord injury. The first step is to estimate the risks and tolerance of cell transplantation in a man. The fate of stem cells (multipotent or pluripotent) in the body is still poorly understood, and it is not excluded that uncontrolled cell multiplications occur, leading to the appearance of teratomas (tumor developed from pluripotent cells).
Advantages are:
* The safety of the cells also seems to be proven (in short term)
* Rats transplanted seven days after the injury had benefited from reactivation of myelinization of neurons by oligodendrocytes, attenuation of motor neuron loss and improvement of limb motor function.
The disadvantages are:
* Constraints of the ethical and religious order, it is necessary the consent and the approval of the donor and the recipient for the transplant to take place.
* The development of the technique is still new, there is a chance that side effects of the transplant appear years after the operation.
Organisms,such as hawks and leopards, that obtain their energy from foods they consume are called :
b) heterotrophs
<span>Ultradian rhythm which is occuring 24 hours a day. There are different cycles in human body Ultradian rythm, circadian rythm and infradian rhythm. The sleep cycle occurs 24 hour a day. Such cycles are called Ultradian rhythm. Blood circulation, blinking etc are also exmples for Ultradian rhythms.</span>
<span>By using genetic engineering techniques to transform bacteria that produce the enzyme I will extract the DNA from the cells of different people who can make the enzyme digestion. Then will cut the DNA with a restriction enzyme, and use gel electrophoresis and a DNA probe to locate the gene. By using the polymerase chain reaction I will copy the gene. Thereafter, I will choose a plasmid that has an antibiotic resistance genetic marker, and cut the plasmid with the same restriction enzyme used to cut out the human gene.
Later I will insert the copies of the human gene into the plasmids and allow the bacterial cells to take in the plasmids. Later, I will allow the bacteria to grow in a culture containing the antibiotic. And hence, these bacteria will make the digestion enzyme.</span>
