Makalah | Laporan Pendahuluan | Asuhan Keperawatan | Tips Sehat | Celana Olahraga | News

Cloning "makes human embryonic stem cells

Cloning "makes human embryonic stem cells
A form of cloning has been used to create customized communications embryonic stem cells in humans, researchers say.

The genetic material was taken from a skin cell of an adult and transferred to a human egg. This is grown to produce an early embryo.

Stem cells have enormous potential in medicine because they can become any cell in the body.

However, stem cells are chromosomes contained both adults and eggs.

The technique used - the somatic cell nuclear transfer - rose to fame in 1997 when Dolly, the first mammal cloned from an adult cell, was released to the world.

A South Korean scientist Hwang Woo-suk, had stated that have created stem cells from cloned human embryos, but was found to have falsified evidence.

The principal investigator in the New York Stem Cell Foundation Laboratory, Dr. Dieter Egli, said there was "a big question" about whether the cloning technique could be used reliably in humans.

Dolly the sheep

He said other "groups had tried before, but no."

Writing in the journal Nature, said his group had also failed with traditional techniques.

When they removed the egg's genetic material and replaced it with the chromosomes of a skin cell, the egg divided, but not go beyond the cell stage 12.06.

However, hatching own genetic material into the place and added the skin of the chromosomes, the egg developed. It reached the blastocyst stage, which can contain up to 100 cells and is the usual source of embryonic stem cells.


Egg and sperm both have one set of chromosomes, which means that adults with two copies of each chromosome.

In this technique, two adult specimens are added to the copy in the egg is, a total of three, which can be problematic.
Read the main story
Why stem cells?

Many diseases are impossible to treat. As the researchers put it "can not be cured, can only be served."

Stem cells are one of the great hopes of medicine because they can become any other type of cell - nerve, heart, bones, skin, liver, etc.

Create heart cells and it may be possible to repair the damage from a heart attack. Insulin-producing cells are destroyed in patients with type 1 diabetes, but stem cells may one day be used to grow.

Because clinical trials are ongoing. The first trial with embryonic stem cells in Europe, testing a treatment for progressive loss of vision, has begun in London.

However, this does not use the patient's own cells. Immunosuppressive drugs are likely to be needed to prevent rejection. This is the reason for making stem cells from cells of the body is perceived as a gold standard of medicine.
Embryonic stem cell test advantage

Often the embryos without the correct number of chromosomes do not develop at all. Down syndrome is caused by three copies of a single chromosome.

Researchers need to produce embryonic cells that have a single donor DNA, however, once the egg begins to divide the chromosomes are combined in the core and would be almost impossible to separate.

Dr. Egli told the BBC. "The cells that we have still not for therapeutic use is evident that there is more work to do, this is the first day.

"We see this as a step in that direction, so now we know that a human egg can make a specialized adult cell, like a skin cell, a stem cell."

Prof. Mary Herbert, of the Institute for Ageing and Health at Newcastle University, said: "This study shows that the conventional approach to somatic cell nuclear transfer is inefficient in humans.

"However, the authors were able to increase efficiency by letting the host oocyte [egg] genome in place.

"While this approach is not a solution in itself, brings us one step closer to understanding where the problems are."
No embryos required

Recently, a different route to stem cells has been used. Instead of using an egg, a chemical toilet "reprogramming" an adult cell into a stem cell.

While this is seen as more ethical, there are doubts about whether the cells could be used for therapeutic purposes. There are differences between embryos and "induced" stem cells, the latter being more likely to express genes that cause cancer.

Professor Robin Lovell-Badge, National Institute of the UK Medical Research, said: "This work will be considered significant, both for those who are trying to use somatic cell nuclear transfer to produce patient-specific human the Embryonic stem cell lines and those who oppose human experiments 'cloning'. "
Cloning "makes human embryonic stem cells

Cloning "makes human embryonic stem cells Rating: 4.5 Diposkan Oleh: kiki norfiyanti

0 comments:

Poskan Komentar

Silahkan berkomentar kawan