单选题
According to scientists in the USA, stem cell therapy may one day be able to repair the hearts of people with heart failure. Researchers at Pittsburgh University School of Medicine examined 20 patients who had severe heart failure and were going to have surgery.
They injected stem cells into the parts of their hearts that were damaged. They then compared their hearts with those of people who had undergone surgery without having the stem cells injected into them (they had also suffered from severe heart failure). The patients who had had the stem cells injected had hearts that were able to pump (用泵抽取) more blood than the others.
According to Professor Robert Kormos, one of the researchers, these results could revolutionize heart treatment. Although previous studies had indicated that there might be a benefit, this is the first study that has actually proved that stem cell therapy can help the failing heart work better.
All the patients in this study had hearts that could not pump blood properly. The scientists measured their ejection fraction (射血分数). It is a measure of heart performance; you measure how much blood is being pumped out by the left ventricle (心室).
Healthy people"s ejection fraction is about 55%. These patients had ejection fraction of under 35%. They all had by-pass surgery (搭桥手术) performed on them. Some of the patients had stem cells taken from their hip bones and injected into 25—30 sites in the damaged heart muscle. Six months later their ejection fraction rate was 46.1% while those who just had surgery but no stem cell injections averaged 37.2%.
No side effects were reported.
Heart failure is a common problem all over the world. In the UK alone about 650,000 people suffer from heart failure every year. As the number of people suffering from heart failure increases in the world in general these findings are particularly significant.
Current treatments relieve the symptoms. This new stem cell therapy actually repairs the damaged muscle in the heart and has the potential of curing the disease.

单选题 The 20 patients had stem cell injections instead of surgery.

单选题 The experiment proved to be satisfactory.

单选题 The control group patients regretted not having had stem cell injections.

单选题 The study actually proved for the first time the benefit of stem cell therapy.

单选题 The ejection fraction rate of the patients with stem cell injections decreased.

单选题 Heart failure is more common in the UK than anywhere else in the world.

单选题 Stem cell therapy seems to have great prospects.