共用题干 Stem Cell Therapy May Help Repair the HeartAccording 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

题目
共用题干
Stem Cell Therapy May Help Repair the Heart
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（用泵抽运）
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）.This 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.

The 20 patients had stem cell injections instead of surgery.
A:Right
B:Wrong
C:Not mentioned
相似考题

1.共用题干 Napping to a Healthier Heart?1 Researchers say they have developed a simple test that can tell if a person with heart disease is likely to suffer a heart attack.The test measures levels of a protein in the blood.The researchers say people with high levels of this protein are at high risk of heart attack,heart failure or stroke.2 Kirsten Bibbins-Domingo of the University of California in San Francisco led the team.For about four years,they studied almost one thousand patients with heart disease.The researchers tested the heart disease patients for a protein called NT-proBNP. Patients with the highest levels were nearly eight times more likely than those with the lowest levels to have a heart attack,heart failure or stroke.3 The researchers say the presence of high levels of the protein in the blood shows that the heart muscle is under pressure in some way.The study involved mostly men,so the researchers could not say for sure that the results are also true for women.They say the patients with the highest levels of NT-proBNP were older and had other problems like diabetes or high blood pressure.4 Other researchers say more studies are needed to confirm if knowing the protein levels of a heartdisease patient should affect that person’s treatment.They also would like to know if more aggressive treatment could reduce the patient's chance of a heart attack or stroke.The study appeared in theJournal of the American Medical Association.5 Could a little sleep during the middle of the day reduce the risk of a heart attack?An unrelatedstudy earlier this month in the Archives of Internal Medicine suggests that the answer may be yes.In countries like the United States,afternoon naps are mostly for children. But they are common for adults in Mediterranean countries.And these countries generally have lower rates of heart disease.So scientists in theUnited States and Greece wondered if naps could play a part.Twenty-three thousand healthy adults took part in the study by Harvard University and the University of Athens.Those who took thirty-minute naps three times a week had a thirty-seven percent lower risk of death from heart problems than people who did not takenaps.6 The researchers say napping may improve heart health by reducing stress.They say the researchsuggests that naps are especially good for working men.But they say not enough female subjects died during the study to judge the benefits for women.If a person has a high level of NT-proBNP_________.A: where fewer pepole die from heart problemB:whether they have the risk of heart attack,heart failure or stroke C:would probably have lower rates of heart diseaseD:how to test a person's NT-proBNP level in the blood by himselfE:his heart muscle would be under pressure in some wayF:that napping is of great benefit to women too

2.共用题干 Napping to a Healthier Heart?1 Researchers say they have developed a simple test that can tell if a person with heart disease is likely to suffer a heart attack.The test measures levels of a protein in the blood.The researchers say people with high levels of this protein are at high risk of heart attack,heart failure or stroke.2 Kirsten Bibbins-Domingo of the University of California in San Francisco led the team.For about four years,they studied almost one thousand patients with heart disease.The researchers tested the heart disease patients for a protein called NT-proBNP.Patients with the highest levels were nearly eight times more likely than those with the lowest levels to have a heart attack,heart failure or stroke.3 The researchers say the presence of high levels of the protein in the blood shows that the heart muscle is under pressure in some way.The study involved mostly men,so the researchers could not say for sure that the results are also true for women.They say the patients with the highest levels of NT-proBNP were older and had other problems like diabetes or high blood pressure.4 Other researchers say more studies are needed to confirm if knowing the protein levels of a heart disease patient should affect that person's treatment.They also would like to know if more aggressive treatment could reduce the patient's chance of a heart attack or stroke.The study appeared in the Journal of the American Medical Association.5 Could a little sleep during the middle of the day reduce the risk of a heart attack?An unrelated study earlier this month in the Archives of Internal Medicine suggests that the answer may be yes.In countries like the United States,afternoon naps are mostly for children.But they are common for adults in Mediterranean countries.And these countries generally have lower rates of heart disease.So scientists in the United States and Greece wondered if naps could play a part.Twenty-three thousand healthy adults took part in the study by Harvard University and the University of Athens.Those who took thirty-minute naps three times a week had a thirty-seven percent lower risk of death from heart problems than people who did not take naps.6 The researchers say napping may improve heart health by reducing stress.They say the research suggests that naps are especially good for working men.But they say not enough female subjects died during the study to judge the benefits for women.According to some researchers,by measuring the levels of NT-proBNP in the blood people may know______.A:where fewer people die from heart problemB:whether they have the risk of heart attack,heart failure or strokeC:would probably have lower rates of heart diseaseD:how to test a person's NT-proBNP level in the blood by himselfE:his heart muscle would be under pressure in some wayF:that napping is of great benefit to women too

3.共用题干 Napping to a Healthier Heart?1 Researchers say they have developed a simple test that can tell if a person with heart disease is likely to suffer a heart attack.The test measures levels of a protein in the blood.The researchers say people with high levels of this protein are at high risk of heart attack,heart failure or stroke.2 Kirsten Bibbins-Domingo of the University of California in San Francisco led the team.For about four years,they studied almost one thousand patients with heart disease.The researchers tested the heart disease patients for a protein called NT-proBNP.Patients with the highest levels were nearly eight times more likely than those with the lowest levels to have a heart attack,heart failure or stroke.3 The researchers say the presence of high levels of the protein in the blood shows that the heart muscle is under pressure in some way.The study involved mostly men,so the researchers could not say for sure that the results are also true for women.They say the patients with the highest levels of NT-proBNP were older and had other problems like diabetes or high blood pressure.4 Other researchers say more studies are needed to confirm if knowing the protein levels of a heart disease patient should affect that person's treatment.They also would like to know if more aggressive treatment could reduce the patient's chance of a heart attack or stroke.The study appeared in the Journal of the American Medical Association.5 Could a little sleep during the middle of the day reduce the risk of a heart attack?An unrelated study earlier this month in the Archives of Internal Medicine suggests that the answer may be yes.In countries like the United States,afternoon naps are mostly for children.But they are common for adults in Mediterranean countries.And these countries generally have lower rates of heart disease.So scientists in the United States and Greece wondered if naps could play a part.Twenty-three thousand healthy adults took part in the study by Harvard University and the University of Athens.Those who took thirty-minute naps three times a week had a thirty-seven percent lower risk of death from heart problems than people who did not take naps.6 The researchers say napping may improve heart health by reducing stress.They say the research suggests that naps are especially good for working men.But they say not enough female subjects died during the study to judge the benefits for women.Paragraph 5______A:More Questions to Be AskedB:Older Males Have Higher Levels of NT-proBNPC:Development of a Simple But Important TestD:Evidence of Positive Relationship Between Napping and Heart DiseaseE:How to Control the Levels of NT-proBNPF:Effects of NT-proBNP on Heart Disease

4.共用题干 Napping to a Healthier Heart?1 Researchers say they have developed a simple test that can tell if a person with heart disease is likely to suffer a heart attack.The test measures levels of a protein in the blood.The researchers say people with high levels of this protein are at high risk of heart attack,heart failure or stroke.2 Kirsten Bibbins-Domingo of the University of California in San Francisco led the team.For about four years,they studied almost one thousand patients with heart disease.The researchers tested the heart disease patients for a protein called NT-proBNP. Patients with the highest levels were nearly eight times more likely than those with the lowest levels to have a heart attack,heart failure or stroke.3 The researchers say the presence of high levels of the protein in the blood shows that the heart muscle is under pressure in some way.The study involved mostly men,so the researchers could not say for sure that the results are also true for women.They say the patients with the highest levels of NT-proBNP were older and had other problems like diabetes or high blood pressure.4 Other researchers say more studies are needed to confirm if knowing the protein levels of a heartdisease patient should affect that person’s treatment.They also would like to know if more aggressive treatment could reduce the patient's chance of a heart attack or stroke.The study appeared in theJournal of the American Medical Association.5 Could a little sleep during the middle of the day reduce the risk of a heart attack?An unrelatedstudy earlier this month in the Archives of Internal Medicine suggests that the answer may be yes.In countries like the United States,afternoon naps are mostly for children. But they are common for adults in Mediterranean countries.And these countries generally have lower rates of heart disease.So scientists in theUnited States and Greece wondered if naps could play a part.Twenty-three thousand healthy adults took part in the study by Harvard University and the University of Athens.Those who took thirty-minute naps three times a week had a thirty-seven percent lower risk of death from heart problems than people who did not takenaps.6 The researchers say napping may improve heart health by reducing stress.They say the researchsuggests that naps are especially good for working men.But they say not enough female subjects died during the study to judge the benefits for women.According to some researchers,by measuring the levels of NT-proBNP in the blood people mayknow ________.A: where fewer pepole die from heart problemB:whether they have the risk of heart attack,heart failure or stroke C:would probably have lower rates of heart diseaseD:how to test a person's NT-proBNP level in the blood by himselfE:his heart muscle would be under pressure in some wayF:that napping is of great benefit to women too

更多“共用题干 Stem Cell Therapy May Help Repair the HeartAccording 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”相关问题

  • 第1题：

    共用题干
    Napping to a Healthier Heart?
    1 Researchers say they have developed a simple test that can tell if a person with heart disease is likely to suffer a heart attack.The test measures levels of a protein in the blood.The researchers say people with high levels of this protein are at high risk of heart attack,heart failure or stroke.
    2 Kirsten Bibbins-Domingo of the University of California in San Francisco led the team.For about four years,they studied almost one thousand patients with heart disease.The researchers tested the heart disease patients for a protein called NT-proBNP.Patients with the highest levels were nearly eight times more likely than those with the lowest levels to have a heart attack,heart failure or stroke.
    3 The researchers say the presence of high levels of the protein in the blood shows that the heart muscle is under pressure in some way.The study involved mostly men,so the researchers could not say for sure that the results are also true for women.They say the patients with the highest levels of NT-proBNP were older and had other problems like diabetes or high blood pressure.
    4 Other researchers say more studies are needed to confirm if knowing the protein levels of a heart disease patient should affect that person's treatment.They also would like to know if more aggressive treatment could reduce the patient's chance of a heart attack or stroke.The study appeared in the Journal of the American Medical Association.
    5 Could a little sleep during the middle of the day reduce the risk of a heart attack?An unrelated study earlier this month in the Archives of Internal Medicine suggests that the answer may be yes.In countries like the United States,afternoon naps are mostly for children.But they are common for adults in Mediterranean countries.And these countries generally have lower rates of heart disease.So scientists in the United States and Greece wondered if naps could play a part.Twenty-three thousand healthy adults took part in the study by Harvard University and the University of Athens.Those who took thirty-minute naps three times a week had a thirty-seven percent lower risk of death from heart problems than people who did not take naps.
    6 The researchers say napping may improve heart health by reducing stress.They say the research suggests that naps are especially good for working men.But they say not enough female subjects died during the study to judge the benefits for women.

    If a person has a high level of NT-proBNP______.
    A:where fewer people die from heart problem
    B:whether they have the risk of heart attack,heart failure or stroke
    C:would probably have lower rates of heart disease
    D:how to test a person's NT-proBNP level in the blood by himself
    E:his heart muscle would be under pressure in some way
    F:that napping is of great benefit to women too

    答案：E
    解析：
    第二段主要介绍了加利福尼亚大学一个团队所进行的研究。通过检查心脏病人的NT-proBNP水平，发现水平最高的病人与水平最低的病人之间患心脏病的可能性相差近8倍。
    第三段说到，研究涉及的多是男性，并发现年老且患有糖尿病或高血压者NT-proBNP的水平最高。
    由第四段的内容可知，其他研究者认为还要确认一些问题，如心脏病病人的蛋白质水平是否影响其治疗；他们还想知道更多的积极治疗能否减少病人得心脏病或中风的机会。
    第五段说到，地中海国家的成年人普遍都午睡，而且患心脏病的几率较低。哈佛大学和雅典大学的研究证明，每周午睡三次，每次30分钟的人比完全不午睡的人死于心脏病的几率低37%。
    由第一段最后两句可知，研究人员检测血液中蛋白质的水平，他们称血液中这种蛋白质水平高的人得心脏病或中风的几率高，故选B。
    由第三段第一句可知，血液中含有高浓度的该种蛋白质证明心肌受到了压迫。
    由文章第五段的内容可知，定期午睡的人患心脏病的几率更低。
    由第三段第二句和文章的最后一句可知，研究对象多为男性，并且由于在调查期间女性研究对象死亡的并不多，所以无法判断午睡对女性的影响。

  • 第2题：

    共用题干
    Napping to a Healthier Heart?
    1 Researchers say they have developed a simple test that can tell if a person with heart disease is likely to suffer a heart attack.The test measures levels of a protein in the blood.The researchers say people with high levels of this protein are at high risk of heart attack,heart failure or stroke.
    2 Kirsten Bibbins-Domingo of the University of California in San Francisco led the team.For about four years,they studied almost one thousand patients with heart disease.The researchers tested the heart disease patients for a protein called NT-proBNP.Patients with the highest levels were nearly eight times more likely than those with the lowest levels to have a heart attack,heart failure or stroke.
    3 The researchers say the presence of high levels of the protein in the blood shows that the heart muscle is under pressure in some way.The study involved mostly men,so the researchers could not say for sure that the results are also true for women.They say the patients with the highest levels of NT-proBNP were older and had other problems like diabetes or high blood pressure.
    4 Other researchers say more studies are needed to confirm if knowing the protein levels of a heart disease patient should affect that person's treatment.They also would like to know if more aggressive treatment could reduce the patient's chance of a heart attack or stroke.The study appeared in the Journal of the American Medical Association.
    5 Could a little sleep during the middle of the day reduce the risk of a heart attack?An unrelated study earlier this month in the Archives of Internal Medicine suggests that the answer may be yes.In countries like the United States,afternoon naps are mostly for children.But they are common for adults in Mediterranean countries.And these countries generally have lower rates of heart disease.So scientists in the United States and Greece wondered if naps could play a part.Twenty-three thousand healthy adults took part in the study by Harvard University and the University of Athens.Those who took thirty-minute naps three times a week had a thirty-seven percent lower risk of death from heart problems than people who did not take naps.
    6 The researchers say napping may improve heart health by reducing stress.They say the research suggests that naps are especially good for working men.But they say not enough female subjects died during the study to judge the benefits for women.

    People who take regular afternoon naps______.
    A:where fewer people die from heart problem
    B:whether they have the risk of heart attack,heart failure or stroke
    C:would probably have lower rates of heart disease
    D:how to test a person's NT-proBNP level in the blood by himself
    E:his heart muscle would be under pressure in some way
    F:that napping is of great benefit to women too

    答案：C
    解析：
    第二段主要介绍了加利福尼亚大学一个团队所进行的研究。通过检查心脏病人的NT-proBNP水平，发现水平最高的病人与水平最低的病人之间患心脏病的可能性相差近8倍。
    第三段说到，研究涉及的多是男性，并发现年老且患有糖尿病或高血压者NT-proBNP的水平最高。
    由第四段的内容可知，其他研究者认为还要确认一些问题，如心脏病病人的蛋白质水平是否影响其治疗；他们还想知道更多的积极治疗能否减少病人得心脏病或中风的机会。
    第五段说到，地中海国家的成年人普遍都午睡，而且患心脏病的几率较低。哈佛大学和雅典大学的研究证明，每周午睡三次，每次30分钟的人比完全不午睡的人死于心脏病的几率低37%。
    由第一段最后两句可知，研究人员检测血液中蛋白质的水平，他们称血液中这种蛋白质水平高的人得心脏病或中风的几率高，故选B。
    由第三段第一句可知，血液中含有高浓度的该种蛋白质证明心肌受到了压迫。
    由文章第五段的内容可知，定期午睡的人患心脏病的几率更低。
    由第三段第二句和文章的最后一句可知，研究对象多为男性，并且由于在调查期间女性研究对象死亡的并不多，所以无法判断午睡对女性的影响。

  • 第3题：

    共用题干
    Stem Cell Therapy May Help Repair the Heart
    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（用泵抽运）
    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）.This 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.

    Stem cell therapy seems to have great prospects.
    A:Right
    B:Wrong
    C:Not mentioned

    答案：A
    解析：

  • 第4题：

    共用题干
    Stem Cell Therapy May Help Repair the Heart
    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（用泵抽运）
    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）.This 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.

    The ejection fraction rate of the patients with stem cell injections decreased.
    A:Right
    B:Wrong
    C:Not mentioned

    答案：B
    解析：

  • 第5题：

    共用题干
    第一篇

    Human Heart can Make New Cells

    Solving a longstanding（为时甚久的）mystery, scientists have found that the human heart continues to
    generate new cardiac（心脏的）cells throughout the life span, although the rate of new cell production slows
    with age.
    The finding,published in the April 3rd issue of Science,could open a new path for the treatment of heart
    diseases such as heart failure and heart attack,experts say.
    "We find that the beating cells in the heart, cardiomyocytes（心肌细胞）,are renewed," said lead
    researcher Dr. Jonas Frisen,a professor of stem cell research at the Karolinska Institute in Stockholm,
    Sweden."It has previously not been known whether we were limited to the cardiomyocytes we were born with
    or whether they could be renewed,"he said.
    "The process of renewing these cells changes over time,"Frisen added. In a 20-year-old,about 1
    percent of cardiomyocytes are exchanged each year , but the turnover（更替）rate decreases with age to only
    0.45 percent by age 75.
    "If we can understand how the generation of new cardiomyocytes is regulated,it may be potentially
    possible to develop pharmaceuticals（药物）that promote this process to stimulate regeneration after , for
    example,a heart attack,"Frisen said.
    That could lead to treatment that helps restore damaged hearts.
    "A lot of people suffer from chronic heart failure,."noted co-author Dr. Ratan Bhardwaj,also from the
    Karolinska Institute."Chronic heart failure arises from heart cells dying," he said.
    "With this finding,scientists are opening the door to potential therapies（疗法）,to having ourselves heal
    ourselves,"Bhardwaj said."Maybe one could devise a pharmaceutical agent that would make heart cells
    make new and more cells to overcome the problem they are facing."
    But barriers remain.According to Bhardwaj,scientists do not yet know how to increase heart cell
    production to a rate that would replace cells faster than they are dying off,especially in older patients with
    heart failure.In addition,the number of new cells the heart produces was estimated using healthy hearts一
    whether the rate of cell turnover in diseased hearts is the same remains unknown.

    The human heart stops producing cardiac cells ______.
    A:when a person becomes old
    B:as soon as a person gets sick
    C:immediately after a person is born
    D:once a person dies

    答案：D
    解析：
    根据第一段中“…the human heart continues to generate new cardiac（心脏的）cells throughout the life span”可知，在人的整个生命进程中，其心脏持续产生新的心肌细胞。言外之 意，这个过程直到生命结束才会停止。
    根据第二段中“The finding...could open a new path for the treatment of heart diseases”可 知，这个研究成果将为心脏病的治疗开辟新的途径。因此C项符合题意。
    根据第四段中“…but the turnover（更替）rate decreases with age to only 0.45 percent by age 75”可知，C项符合题意。
    根据倒数第三段中“Chronic heart failure arises from heart cells dying”可知，慢性心力衰 竭是由心肌细胞死亡导致的。因此A项符合题意。
    最后一句的大意是：另外，心脏产生的新细胞的数量是按照健康心脏估算的，而患病心脏的细胞更替率是否与健康心脏相同还不得而知。因此C项符合题意。第二篇 本篇文章主要讲述了远古冰人尸体的发现及对其的相关研究情况。

  • 第6题：

    共用题干
    第一篇

    Human Heart can Make New Cells

    Solving a longstanding（为时甚久的）mystery, scientists have found that the human heart continues to
    generate new cardiac（心脏的）cells throughout the life span, although the rate of new cell production slows
    with age.
    The finding,published in the April 3rd issue of Science,could open a new path for the treatment of heart
    diseases such as heart failure and heart attack,experts say.
    "We find that the beating cells in the heart, cardiomyocytes（心肌细胞）,are renewed," said lead
    researcher Dr. Jonas Frisen,a professor of stem cell research at the Karolinska Institute in Stockholm,
    Sweden."It has previously not been known whether we were limited to the cardiomyocytes we were born with
    or whether they could be renewed,"he said.
    "The process of renewing these cells changes over time,"Frisen added. In a 20-year-old,about 1
    percent of cardiomyocytes are exchanged each year , but the turnover（更替）rate decreases with age to only
    0.45 percent by age 75.
    "If we can understand how the generation of new cardiomyocytes is regulated,it may be potentially
    possible to develop pharmaceuticals（药物）that promote this process to stimulate regeneration after , for
    example,a heart attack,"Frisen said.
    That could lead to treatment that helps restore damaged hearts.
    "A lot of people suffer from chronic heart failure,."noted co-author Dr. Ratan Bhardwaj,also from the
    Karolinska Institute."Chronic heart failure arises from heart cells dying," he said.
    "With this finding,scientists are opening the door to potential therapies（疗法）,to having ourselves heal
    ourselves,"Bhardwaj said."Maybe one could devise a pharmaceutical agent that would make heart cells
    make new and more cells to overcome the problem they are facing."
    But barriers remain.According to Bhardwaj,scientists do not yet know how to increase heart cell
    production to a rate that would replace cells faster than they are dying off,especially in older patients with
    heart failure.In addition,the number of new cells the heart produces was estimated using healthy hearts一
    whether the rate of cell turnover in diseased hearts is the same remains unknown.

    It is not known yet if the rate of cell turnover in diseased hearts_________.
    A:is high enough to replace cells faster than they're dying off
    B:is of any use to researchers
    C:is the same as that in healthy hearts
    D:changes over time

    答案：C
    解析：
    根据第一段中“…the human heart continues to generate new cardiac（心脏的）cells throughout the life span”可知，在人的整个生命进程中，其心脏持续产生新的心肌细胞。言外之 意，这个过程直到生命结束才会停止。
    根据第二段中“The finding...could open a new path for the treatment of heart diseases”可 知，这个研究成果将为心脏病的治疗开辟新的途径。因此C项符合题意。
    根据第四段中“…but the turnover（更替）rate decreases with age to only 0.45 percent by age 75”可知，C项符合题意。
    根据倒数第三段中“Chronic heart failure arises from heart cells dying”可知，慢性心力衰 竭是由心肌细胞死亡导致的。因此A项符合题意。
    最后一句的大意是：另外，心脏产生的新细胞的数量是按照健康心脏估算的，而患病心脏的细胞更替率是否与健康心脏相同还不得而知。因此C项符合题意。第二篇 本篇文章主要讲述了远古冰人尸体的发现及对其的相关研究情况。

  • 第7题：

    共用题干
    Cell Phones

    I Believe it or not,cell phones have been around for over a quarter of a century.The first commercial
    cell phone systemfl was developed by the Japancoc in I 979.But cell phones have changed a lot
    since that
    time.The early cell phones were big and heavy but they have developed into small and light palm-sized mod-
    els.There have been huge (lcveloprnents in their functions,too;we have had call forwarding,text messaging,
    answering services and hands-free use for years,but now there are countless new facilities,su,ch as instant ac-
    cess to the Internet and receiving and sending photos.
    2 Cell phones have become very common in our lives;recent statistics suggest as many as one in three
    people cii the planet now have a cell phone,and most of them say they couldn't live without one.Cell phones
    are used in every area of our lives and have become a necessary tool,used for essential arrangements,social
    contact and business.They have made it easier to call for help on the highway.They have made it possible to
    keep in touch with people"on the move”一when people are traveling.
    3 Cell phones have made communication easier and have reduced the need for family arguments.We
    can use cell phones to let our family know we'11 be late or if there’。a sudden change of tian or an emergen-
    cy.Cell phones have eased the worries of millions of parents when their teenagers are out late,they can now
    contact their children at any time.
    4 This does not mean that cell phones are all good news.They have brought with them a number of
    new headaches for their owners;it costs a lot to replace stolen phones,something that is becoming a frequent
    occurrence,and have you ever seen such huge phone bills? More serious,however,is the potential health
    problem they bring:there are fears that radiation from the phones may cause brain tumor（肿瘤）.This may be
    a time bomb waiting to happen to younger people who have grown up with cell phones that they simply can't
    live without!

    Paragraph 3________
    A:Cell Phones and the Family
    B:Commercial Cell Phone Systems
    C:Cell Phones in Everyday Life
    D:Cell Phones for Teenagers
    E:History of Cell Phones
    F:Problems with Cell Phones

    答案：A
    解析：
    第一段开篇就说从手机发明到现在已过去了四分之一多个世纪，又对比了手机早期和 近期在功能一上的不同，由此可知是在叙述手机的历史。
    第二段讲手机在人们的生活中十分常见，许多人离不开手机，手机用于各个场合，因而 意在说明手机存在于日常生活中。
    第三段列举了手机对于家人联系上的作用，有助于减少家庭的误会纠纷，有助于父母 联系孩子，因而讲的是手机同家庭的关系。
    最后一段第一句就说明了该段要讲的是手机带来的问题，段中虽举了青少年的例子，但 不局限于描写青少年，因此选F。
    根据第一段末尾可知答案。
    根据第二段第三行可知答案。
    根据第三段第二句可知答案。
    根据第四段第二句可知答案。第4部分；阅读理解第一篇 本文主要介绍了北极冰川融化的情况、原因和科学家们的担心。

  • 第8题：

    造血干细胞（hemopoietic stem cell）


    正确答案:是存在于造血组织中的一群原始造血细胞，具有自我增生和分化功能，是各种血细胞的共同祖先，可增生分化产生多种功能不同的血细胞。

  • 第9题：

    体细胞基因治疗（somatic cell gene therapy）


    正确答案:是指将正常基因转移到体细胞，使之表达基因产物，以达到治疗目的。这种方法的理想措施是将外源正常基因导入靶体细胞内染色体特定基因座位，用健康的基因确切地替换异常的基因，使其发挥治疗作用，同时还须减少随机插入引起新的基因突变的可能性。

  • 第10题：

    名词解释题
    神经干细胞(neural stem cell)

    正确答案： 神经干细胞，在脑组织中分离出能够不断分裂增殖，具有多分化潜能的细胞群落，根据有丝分裂原反应性的不同，可分为EGF反应型和FGF-2反应型细胞。
    解析： 暂无解析

  • 第11题：

    名词解释题
    骨髓间充质干细胞(marrow mesenchymal stem cell)

    正确答案： 骨髓间充质干细胞，从骨髓中分离出的最具有分化潜能的多能干细胞，可向中胚层和神经外胚层各种不同类型的组织细胞分化。
    解析： 暂无解析

  • 第12题：

    名词解释题
    Embryonic stem cell

    正确答案： 为胚胎干细胞，是由胚泡的内细胞团中分离得到的一种全能性细胞。
    解析： 暂无解析

  • 第13题：

    共用题干
    Napping to a Healthier Heart?

    1 Researchers say they have developed a simple test that can tell if a person with heart disease is
    likely to suffer a heart attack.The test measures levels of a protein in the blood.The researchers say people
    with high levels of this protein are at high risk of heart attack,heart failure or stroke.
    2 Kirsten Bibbins-Domingo of the University of California in San Francisco led the team.For about
    four years,they studied almost one thousand patients with heart disease.The researchers tested the heart
    disease patients for a protein called NT-proBNP. Patients with the highest levels were nearly eight times more
    likely than those with the lowest levels to have a heart attack,heart failure or stroke.
    3 The researchers say the presence of high levels of the protein in the blood shows that the heart
    muscle is under pressure in some way.The study involved mostly men,so the researchers could not say for
    sure that the results are also true for women.They say the patients with the highest levels of NT-proBNP
    were older and had other problems like diabetes or high blood pressure.
    4 Other researchers say more studies are needed to confirm if knowing the protein levels of a heart
    disease patient should affect that person’s treatment.They also would like to know if more aggressive
    treatment could reduce the patient's chance of a heart attack or stroke.The study appeared in the
    Journal of the American Medical Association.
    5 Could a little sleep during the middle of the day reduce the risk of a heart attack?An unrelated
    study earlier this month in the Archives of Internal Medicine suggests that the answer may be yes.In countries
    like the United States,afternoon naps are mostly for children. But they are common for adults in
    Mediterranean countries.And these countries generally have lower rates of heart disease.So scientists in the
    United States and Greece wondered if naps could play a part.Twenty-three thousand healthy adults took part
    in the study by Harvard University and the University of Athens.Those who took thirty-minute naps three
    times a week had a thirty-seven percent lower risk of death from heart problems than people who did not take
    naps.
    6 The researchers say napping may improve heart health by reducing stress.They say the research
    suggests that naps are especially good for working men.But they say not enough female subjects died during
    the study to judge the benefits for women.

    People who take regular afternoon naps _________.
    A: where fewer pepole die from heart problem
    B:whether they have the risk of heart attack,heart failure or stroke
    C:would probably have lower rates of heart disease
    D:how to test a person's NT-proBNP level in the blood by himself
    E:his heart muscle would be under pressure in some way
    F:that napping is of great benefit to women too

    答案：C
    解析：
    由第二段后面两句可知，通过检查心脏病人的NT-proBNP水平，发现水平最高的病人 与水平最低的病人之间患心脏病的可能性相差近8倍。
    第三段说到，研究涉及的多是男性，并发现老年男性且患有糖尿病和高血压者 NT-proBNP的水平最高。
    由第四段的内容可知，其他研究者认为还要确认一些问题，如心脏病病人蛋白质水平 是否影响其治疗；他们还想知道更多的积极治疗能否减少病人得心脏病和中风的机会。
    第五段说到，地中海国家的成年人普遍都午睡，而且患心脏病的几率较低。哈佛大学 和雅典大学的研究证明，每周午睡三次，每次30分钟的人比完全不午睡的人死于心脏病的几 率低37％。
    答案来源于第一段的第二、三句。
    答案来源于第三段第一句。
    答案来源于第五段第一、二句和该段最后一句。
    答案来源于第三段第二句和文章的最后一句。第4部分：阅读理解第一篇 本篇文章主要讲述了普通感冒的传播特点及其预防和治疗。

  • 第14题：

    共用题干
    Stem Cell Therapy May Help Repair the Heart
    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（用泵抽运）
    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）.This 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.

    Heart failure is more common in the UK than anywhere else in the world.
    A:Right
    B:Wrong
    C:Not mentioned

    答案：C
    解析：

  • 第15题：

    共用题干
    Stem Cell Therapy May Help Repair the Heart
    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（用泵抽运）
    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）.This 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.

    The control group patients regretted not having had stem cell injections.
    A:Right
    B:Wrong
    C:Not mentioned

    答案：C
    解析：

  • 第16题：

    共用题干
    Stem Cell Therapy May Help Repair the Heart
    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（用泵抽运）
    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）.This 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.

    The experiment proved to be satisfactory.
    A:Right
    B:Wrong
    C:Not mentioned

    答案：A
    解析：

  • 第17题：

    共用题干
    第一篇

    Human Heart can Make New Cells

    Solving a longstanding（为时甚久的）mystery, scientists have found that the human heart continues to
    generate new cardiac（心脏的）cells throughout the life span, although the rate of new cell production slows
    with age.
    The finding,published in the April 3rd issue of Science,could open a new path for the treatment of heart
    diseases such as heart failure and heart attack,experts say.
    "We find that the beating cells in the heart, cardiomyocytes（心肌细胞）,are renewed," said lead
    researcher Dr. Jonas Frisen,a professor of stem cell research at the Karolinska Institute in Stockholm,
    Sweden."It has previously not been known whether we were limited to the cardiomyocytes we were born with
    or whether they could be renewed,"he said.
    "The process of renewing these cells changes over time,"Frisen added. In a 20-year-old,about 1
    percent of cardiomyocytes are exchanged each year , but the turnover（更替）rate decreases with age to only
    0.45 percent by age 75.
    "If we can understand how the generation of new cardiomyocytes is regulated,it may be potentially
    possible to develop pharmaceuticals（药物）that promote this process to stimulate regeneration after , for
    example,a heart attack,"Frisen said.
    That could lead to treatment that helps restore damaged hearts.
    "A lot of people suffer from chronic heart failure,."noted co-author Dr. Ratan Bhardwaj,also from the
    Karolinska Institute."Chronic heart failure arises from heart cells dying," he said.
    "With this finding,scientists are opening the door to potential therapies（疗法）,to having ourselves heal
    ourselves,"Bhardwaj said."Maybe one could devise a pharmaceutical agent that would make heart cells
    make new and more cells to overcome the problem they are facing."
    But barriers remain.According to Bhardwaj,scientists do not yet know how to increase heart cell
    production to a rate that would replace cells faster than they are dying off,especially in older patients with
    heart failure.In addition,the number of new cells the heart produces was estimated using healthy hearts一
    whether the rate of cell turnover in diseased hearts is the same remains unknown.

    Chronic heart failure is attributed to _________.
    A:the dying heart cells
    B:the effect of pharmaceuticals
    C:the weight of the patient
    D:the life span of a person

    答案：A
    解析：
    根据第一段中“…the human heart continues to generate new cardiac（心脏的）cells throughout the life span”可知，在人的整个生命进程中，其心脏持续产生新的心肌细胞。言外之 意，这个过程直到生命结束才会停止。
    根据第二段中“The finding...could open a new path for the treatment of heart diseases”可 知，这个研究成果将为心脏病的治疗开辟新的途径。因此C项符合题意。
    根据第四段中“…but the turnover（更替）rate decreases with age to only 0.45 percent by age 75”可知，C项符合题意。
    根据倒数第三段中“Chronic heart failure arises from heart cells dying”可知，慢性心力衰 竭是由心肌细胞死亡导致的。因此A项符合题意。
    最后一句的大意是：另外，心脏产生的新细胞的数量是按照健康心脏估算的，而患病心脏的细胞更替率是否与健康心脏相同还不得而知。因此C项符合题意。第二篇 本篇文章主要讲述了远古冰人尸体的发现及对其的相关研究情况。

  • 第18题：

    共用题干
    第一篇

    Human Heart can Make New Cells

    Solving a longstanding（为时甚久的）mystery, scientists have found that the human heart continues to
    generate new cardiac（心脏的）cells throughout the life span, although the rate of new cell production slows
    with age.
    The finding,published in the April 3rd issue of Science,could open a new path for the treatment of heart
    diseases such as heart failure and heart attack,experts say.
    "We find that the beating cells in the heart, cardiomyocytes（心肌细胞）,are renewed," said lead
    researcher Dr. Jonas Frisen,a professor of stem cell research at the Karolinska Institute in Stockholm,
    Sweden."It has previously not been known whether we were limited to the cardiomyocytes we were born with
    or whether they could be renewed,"he said.
    "The process of renewing these cells changes over time,"Frisen added. In a 20-year-old,about 1
    percent of cardiomyocytes are exchanged each year , but the turnover（更替）rate decreases with age to only
    0.45 percent by age 75.
    "If we can understand how the generation of new cardiomyocytes is regulated,it may be potentially
    possible to develop pharmaceuticals（药物）that promote this process to stimulate regeneration after , for
    example,a heart attack,"Frisen said.
    That could lead to treatment that helps restore damaged hearts.
    "A lot of people suffer from chronic heart failure,."noted co-author Dr. Ratan Bhardwaj,also from the
    Karolinska Institute."Chronic heart failure arises from heart cells dying," he said.
    "With this finding,scientists are opening the door to potential therapies（疗法）,to having ourselves heal
    ourselves,"Bhardwaj said."Maybe one could devise a pharmaceutical agent that would make heart cells
    make new and more cells to overcome the problem they are facing."
    But barriers remain.According to Bhardwaj,scientists do not yet know how to increase heart cell
    production to a rate that would replace cells faster than they are dying off,especially in older patients with
    heart failure.In addition,the number of new cells the heart produces was estimated using healthy hearts一
    whether the rate of cell turnover in diseased hearts is the same remains unknown.

    In people in their mid-70s,only 0.45 percent of cardiomyocytes______.
    A:are still functional
    B:are reduced each year
    C:are replaced each year
    D:are damaged each year

    答案：C
    解析：
    根据第一段中“…the human heart continues to generate new cardiac（心脏的）cells throughout the life span”可知，在人的整个生命进程中，其心脏持续产生新的心肌细胞。言外之 意，这个过程直到生命结束才会停止。
    根据第二段中“The finding...could open a new path for the treatment of heart diseases”可 知，这个研究成果将为心脏病的治疗开辟新的途径。因此C项符合题意。
    根据第四段中“…but the turnover（更替）rate decreases with age to only 0.45 percent by age 75”可知，C项符合题意。
    根据倒数第三段中“Chronic heart failure arises from heart cells dying”可知，慢性心力衰 竭是由心肌细胞死亡导致的。因此A项符合题意。
    最后一句的大意是：另外，心脏产生的新细胞的数量是按照健康心脏估算的，而患病心脏的细胞更替率是否与健康心脏相同还不得而知。因此C项符合题意。第二篇 本篇文章主要讲述了远古冰人尸体的发现及对其的相关研究情况。

  • 第19题：

    共用题干
    Cell Phones

    I Believe it or not,cell phones have been around for over a quarter of a century.The first commercial
    cell phone systemfl was developed by the Japancoc in I 979.But cell phones have changed a lot
    since that
    time.The early cell phones were big and heavy but they have developed into small and light palm-sized mod-
    els.There have been huge (lcveloprnents in their functions,too;we have had call forwarding,text messaging,
    answering services and hands-free use for years,but now there are countless new facilities,su,ch as instant ac-
    cess to the Internet and receiving and sending photos.
    2 Cell phones have become very common in our lives;recent statistics suggest as many as one in three
    people cii the planet now have a cell phone,and most of them say they couldn't live without one.Cell phones
    are used in every area of our lives and have become a necessary tool,used for essential arrangements,social
    contact and business.They have made it easier to call for help on the highway.They have made it possible to
    keep in touch with people"on the move”一when people are traveling.
    3 Cell phones have made communication easier and have reduced the need for family arguments.We
    can use cell phones to let our family know we'11 be late or if there’。a sudden change of tian or an emergen-
    cy.Cell phones have eased the worries of millions of parents when their teenagers are out late,they can now
    contact their children at any time.
    4 This does not mean that cell phones are all good news.They have brought with them a number of
    new headaches for their owners;it costs a lot to replace stolen phones,something that is becoming a frequent
    occurrence,and have you ever seen such huge phone bills? More serious,however,is the potential health
    problem they bring:there are fears that radiation from the phones may cause brain tumor（肿瘤）.This may be
    a time bomb waiting to happen to younger people who have grown up with cell phones that they simply can't
    live without!

    Cell phones are common in our lives and have become_________.
    A:a necessity
    B:an emergency
    C:a number of new hcadaches
    D:family arguments
    F:big and light palm-sized models
    F:countless new facilities

    答案：A
    解析：
    第一段开篇就说从手机发明到现在已过去了四分之一多个世纪，又对比了手机早期和 近期在功能一上的不同，由此可知是在叙述手机的历史。
    第二段讲手机在人们的生活中十分常见，许多人离不开手机，手机用于各个场合，因而 意在说明手机存在于日常生活中。
    第三段列举了手机对于家人联系上的作用，有助于减少家庭的误会纠纷，有助于父母 联系孩子，因而讲的是手机同家庭的关系。
    最后一段第一句就说明了该段要讲的是手机带来的问题，段中虽举了青少年的例子，但 不局限于描写青少年，因此选F。
    根据第一段末尾可知答案。
    根据第二段第三行可知答案。
    根据第三段第二句可知答案。
    根据第四段第二句可知答案。第4部分；阅读理解第一篇 本文主要介绍了北极冰川融化的情况、原因和科学家们的担心。

  • 第20题：

    定向干细胞（committed stem cell）


    正确答案:由造血干细胞增生分化而形成，包括多能定向干细胞和单能定向干细胞，是造血干细胞与成熟的子代细胞之间的过度类型。

  • 第21题：

    名词解释题
    neural stem cell，NSCs (神经干细胞)

    正确答案： 主要有两类：神经嵴干细胞（neuralcreststemcell，NC-SC）和中枢神经干细胞（CNS-SC）。NCSC为外周神经干细胞（PNS-SC），既可发育为外周神经细胞、神经内分泌细胞和Schwann氏细胞，也能分化为色素细胞（pigmented cell）和平滑肌细胞等。NSC一般是指存在于脑部的中枢神经干细胞（CNS-SC），其子代细胞能分化成为神经系统的大部分细胞。以往认为，中枢神经系统的神经元在出生前或出生后不久，就失去再生能力。但近年的一些研究表明，成年哺乳动物的脑组织仍可不断产生新的神经元，成人脑组织中同样存在NSC。
    目前多使用基因转移的方法，建立神经干细胞系，即诱导NSC的细胞周期不断循环往复，从而阻止其分化过程。永生化的NSC具有较好的生物学特性，它们能自我复制并在体外大量增殖，在移植人体内后仍具有多向分化潜能，同时可被转染并稳定地表达外源基因。
    解析： 暂无解析

  • 第22题：

    名词解释题
    体细胞基因治疗（somatic cell gene therapy）

    正确答案： 是指将正常基因转移到体细胞，使之表达基因产物，以达到治疗目的。这种方法的理想措施是将外源正常基因导入靶体细胞内染色体特定基因座位，用健康的基因确切地替换异常的基因，使其发挥治疗作用，同时还须减少随机插入引起新的基因突变的可能性。
    解析： 暂无解析

  • 第23题：

    名词解释题
    somatic stem cell (成体干细胞)

    正确答案： 是一类成熟较慢但能自我维持增殖的未分化的细胞，这种细胞存在于各种组织的特定位置上，一旦需要，这些细胞便可按发育途径，先进行细胞分裂，然后经过分化产生出另外一群具有有限分裂能力的细胞群。
    成体干细胞的发育等级较低，是多能或单能干细胞。造血干细胞（hematopoietic stem cell，HSC）和骨髓间质干细胞（mesenhymal stem cell）是熟知的成体干细胞。
    解析： 暂无解析

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