VOA常速英语2007年-Stem Cell Research Dominates 2007 Medical Field

Stem cell research was the major medical and science story this past year, topping the list of achievements that experts say might finally lead to cures for many diseases. Meanwhile, global health officials also cheered progress in managing two killer¹ diseases. VOA's Jessica Berman has this look back at the health and medicine high points of 2007.

Stem cells are the master cells that have the ability to generate any cell in the human body. Scientists say this gives stem cells the potential to cure disease by being manipulated to become healthy or beneficial tissue.

In 2007, two teams of researchers, one in the United States and the other in Japan, announced they had succeeded in turning skin cells into a kind of stem cell, with an ability to transform into different cell types. The breakthrough bypassed the need to use embryonic³ stem cells.

James Thompson of the University of Wisconsin was one of the U.S. researchers who helped manipulate the skin cells. He says the development may help quell⁴ a fierce debate over the use of human embryos⁵ for research purposes

"I believe these new results, while they do not eliminate that controversy⁶, is probably the beginning of the end of that controversy," Thompson said.

American investigators⁷ provided the first evidence that the reprogrammed stem cells can work to cure disease, reversing a red-blood cell disorder⁸ known as sickle⁹ cell disease in mice.

Sickle cell is a genetic¹⁰ blood disease, mostly affecting children of African and Asian descent. In the devastating¹¹ disorder, red blood cells do not carry enough oxygen, causing severe pain and destruction of organs.

Investigators bred a strain of mice to contain the human sickle-cell gene². They then reprogrammed skin cells from the mice to an embryonic-like state, and coaxed¹² them to produce red blood cells.

When the mice received the new blood, they began producing normal blood and their symptoms went away.

In 2007, three men - Mario Capecchi of the University of Utah, Oliver Smithies of the University of North Carolina and Martin Evans of Cardiff University of Wales - won the Nobel Prize in Medicine for creating so-called knock-out mice, animals that make most genetic research possible.

"I would say our research is fundamentally resting upon these discoveries," Goldberg said.

Matthew Goldberg is neurologist at the University of Texas Southwestern in Dallas. He tries to find a cure for Parkinson's disease. His team uses knock-out mice to try to identify which genes¹³ are responsible for causing the debilitating¹⁴ condition.

In knock-out mice, Dr. Goldberg says certain genes have been silenced to mimic¹⁵ human disease.

"By deleting it [the gene], one can analyze¹⁶ what the behavior of the mouse is and what physiological¹⁷ changes occur, and thereby¹⁸ understand the normal function of that gene," he explained.

In 2007, there were also major developments in global public health.

The number of measles¹⁹ cases were slashed²⁰ in Africa by 91 percent, and 68 percent worldwide, thanks to an intensive vaccination²¹ campaign.

The Director of the U.S. Centers for Disease Control, Julie Gerberding, is part of a coalition²² of organizations called the Measles Initiative.

"We are celebrating this incredible progress. But we also have to acknowledge that 242,000 children dying of measles is still way too many," Gerberding said.

The Initiative said it is going to focus on efforts to vaccinate²³ children in South Asia, where most measles cases are now reported.

At the end of 2007, researchers report significant progress in the development of a malaria²⁴ vaccine²⁵. Ninety percent of the one-million children who get malaria worldwide each year live in sub-Saharan Africa.

In a trial in Mozambique, the experimental drug reduced the risk of two-thousand youngsters developing severe malaria by almost 60 percent.

Scientists say the vaccine, which is made by GlaxoSmithKline, could be available in two years.