Stem cell research

South Korean scientist Hwang Woo-suk of Seoul National University is under intense scrutiny over his pioneering work on stem cell research. His team published a study on tailored human stem cells in May in Science, a leading U.S. academic journal. The discovery was vital as it could one day lead to treatment for spinal injuries, for example. Hwang said on Friday he was retracting the paper from Science because of a row over its authenticity, even though he did not doubt his findings. He said a follow-up paper sent to another journal would restore faith. Donated human eggs were hollowed out and skin cells from patients injected into it and then fused. The eggs begin dividing and sometimes become embryos.

Following is some of Hwang's recent work:

THERAPEUTIC CLONING Hwang has said his team cloned the first human embryo for research and developed the first tailored embryonic stem cells. Such advances could eventually lead to cures for such debilitating and deadly diseases as Parkinson's and severe spinal cord injury, by taking skin from a patient to grow custom-made stem cells with that patient's specific genetic material. The process was published in Science earlier this year. It is now under scrutiny.

WORLD STEM CELL BANK South Korea established the bank in October with the aim of keeping the country at the forefront in the field. Stem cells are stored at Seoul National University and made available to international researchers. Hwang resigned his chairmanship from the bank after apologising last month for ethical lapses in his work. Two junior women researchers donated their eggs for the team's work, a practice which has been seen as an ethical violation because research associates could feel they were coerced into making such donations.

HUMAN EMBRYOS Hwang has said he is not intending to clone humans. The early-2004 study could pave the way for the start of therapeutic cloning. Hwang and his team have said they removed the nucleus from a human egg and replaced it with the core of another cell taken from the female donor.

FIGHTING MAD COW DISEASE Hwang said in 2003 that his team had cloned cows with high levels of a protein structure that makes them resistant to mad cow disease. Cow's eggs were injected with somatic cells with a high-level of a protein structure, and cultivated them in surrogate cows. The animals are under a long-term study on effectiveness.