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Spare parts

Spare parts ON NOVEMBER 5, two teams of US scientists announced that they had independently achieved a major breakthrough in biology by growing some "primitive" undifferentiated cells, known as the human embryonic stem cells, by isolating them from human embryos and foetuses. These cells have the capacity to rapidly multiply and grow into any sort of tissue that the human body requires - muscles, bone, brain and heart.

These cells are also capable of replacing tissues of people with various diseases: bone marrow for cancer patients, neurons for people suffering from Alzheimer's disease, even pancreatic cells for people suffering from diabetes.

One of the two independent teams headed by James Thomson, an embryologist at the University of Wisconsin in Madison, reported that these stem cells can evidently survive independently and even took further steps to differentiate them into neural, muscle and bone cells.This initiative was described "tremendous" by the director of the US National Institutes of Health (NIH), Harold Varmus.

The other team led by John D Gearhart of the John Hopkins University's School of Medicine in Baltimore, managed to get the stem cells to survive in a petri dish for nine months. Researchers have already used the stem cells to grow human heart muscles that are now 'throbbing' in the laboratory. However, the scientists warn that a significant amount of work needs to be done before this finding can be put to use in therapies.

There are doubts about whether the scientists can grow these stem cells into specific types of cells or produce literally any tissue in the body. The ability to isolate and purify single cell types will be crucial.

Expectedly, the isolation of the embryonic stem cells has fuelled the ongoing debate over human cloning. A section of scientists fear that such research would offer embryologists a simple method for creating designer babies by inserting favourable genes into an embryo's DNA.

This is one of the reasons why the US Congress has banned the NIH from using the federal money to experiment on embryos or cells that could become a foetus.

So both the research teams were compelled to turn to other sources for funding. They are funded by Geron Corp, a biotechnology firm in Menlo Park in California. To ensure that he did not violate the congressional ban, Thomson conducted his work in a lab that was free of federal-funded equipment. Even the embryos he experimented on were leftovers from fertility clinics, donated by parents. The other team also declared that no federal funds were used in their work.

In spite of all the efforts of evading controversies, these scientists are still not free from attacks. Judie Brown, president of the American Right to Life League, called for the rights of the embryos - potential human beings - from which the stem cells were extracted. "These human beings should be protected by law," she said.

However, the sources of cells were not human beings in a strictly legal sense. The John Hopkins researchers took their sample cells from foetuses that were aborted in early pregnancies, while the Wisconsin team used blastocysts (clusters of cells that emerge from the egg a few days after fertilisation) that were donated by couples possessing extra blastocysts.

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