医学英语试题(4)
Smog damages the lungs of growing infants and causes asthma, suggests unpublished research carried out at theUniversity of California at Davis. The findings confirm a link that has been widely suspected, but never proven.
In the past ten years, studies have found circumstantial evidence, one of the more noxious constituents of smog. However, researchers have not proved that ozone causes asthma because they cannot measure how much ozone an individual has been exposed to.
To settle the issue, the Davis carried out a series of experiments with young rhesus monkeys. One group of monkeys had ozone added to their air supply. A second group breathed air containing the dust mite allergen, a component of household dust that is a common trigger of asthma attacks. A third group breathed air containing both the allergen and ozone, and a fourth group breathed clean air.
The amount of ozone in the contaminated air supply was varied to mimic conditions in the real world, says Charles Plopper, one of the team’s leaders. For five days the monkeys breathed air containing ozone, followed by nine ozone-free days—a cycle based loosely on Environmental Protection Agency records of ozone levels in Los Angeles, says Plopper. The concentration of ozone was 0.5 parts per million. “ That is high for California,” he says, “ but about average for Mexico City.”
After five months of exposure, monkeys that had been breathing ozone developed symptoms similar to those of a child with borderline asthma, says Plopper. Heir lung capacity was reduced and they wheezed when briefly exposed to the dust mite allergen. Monkeys that had continually breathed both ozone and the allergen had more severe reactions, similar to full-blown asthma attacks: rapid, shallow breathing and decreased blood oxygen levels.
Both groups of ozone-exposed monkeys had lung abnormalities typical of people with asthma. The smooth muscle that controls the flow of air through the lungs was hyperactive, constricting the airways. The lungs made more mucus than usual, clogging up the airways. And the monkeys has unusually low levels of glutathione(谷胱甘肽), a chemical that protects the lungs from free radicals. “ That puts them at risks for other types of lung injury.” Plopper says.
He and his colleagues had previously found that ozone does not cause the same degree of lung damage in adult monkeys. They believe, therefore, that ozone exposure is especially damaging early in life, when the lungs are still developing.
Because lung development is similar in monkeys and humans, the research may help explain why children who grow up in smoggy cities tend to have more respiratory problems, says Ira Tager of the University of California, Berkeley, School ofPublic Health. “ It fits well with what’s known in humans about developmental effects.” He says.
56. To prove the link between asthma and ozone exposure, according to the passage, is to _________.
A) verify the association between smog and ozone
B) measure the amount of ozone exposure
C) prove the existence of ozone in smog
D)confirm the toxicity of ozone
57. In the test, the subjects _________.
A)were divided into four groups to breathe varied concentrations of ozone
B)inhaled the contaminated air in California and Mexico City respectively
C)had their asthma attacks induced by breathing air containing ozone
D)inhaled the adjusted amount of ozone as if in the real world
58. Which of the following groups turned out to be the most serious victims?
A) The 1st group
B) The 2nd group
C) The 3rd group
D)The 4th group
59. Between the ozone –exposed monkeys’ lung abnormalities and those of people with asthma, the researchers ________.
A)discovered the same amount of ozone exposure
B)pinpointed the exactly same causative factor
C) found a cause-effect relation
D) can draw an analogy.
60. From the results, Plopper would say that ozone exposure _________.
A) can be responsible for the asthma epidemic in children
B) damages monkeys as well as humans
C) affects human lung development
D)all of the above
Passage 5
To beat leukemia, it helps to be lucky. A bone marrow transplant can give a patient a fresh start at producing blood cells free of this cancer, but a successful transplant typically requires that at least five out of six key genetic markers in the donor match those in the recipient.
Unfortunately, most patients don't find a good match even among close relatives willing to donate bone marrow and must hope to get appropriate bone marrow from a tissue bank. Some wait months for a good match, and others die waiting. Some acutely ill patients, having little choice, must accept the best available transplant--blood in which only three or four of the six markers are correct. Having a mismatched donor worsens the recipient's survival odds because the transplanted tissue is often rejected.
A study in the Oct. 22 New England Journal of Medicine brightens the picture for leukemia patients. By giving them a massive dose of stem cells--the marrow cells that harbor blueprints for new, healthy blood cells--researchers in Israel andItaly find they can overwhelm a recipient's remaining immune cells and thwart rejection. The dose of stem cells, collected from blood instead of bone marrow, is up to 10 times greater than a marrow transplant would normally provide.
Even when the donated stem cells are mismatched for three of the six markers, the survival rate of recipients approaches that of patients receiving blood from well-matched, unrelated donors.
In both the marrow and new stem-cell transplant procedures, patients typically receive radiation treatment, chemotherapy, and drugs to suppress immune rejection and ward off disease. Even so, the patients can encounter a cancer recurrence, infection, transplant rejection, or graft-versus-host disease, in which the donor's immune cells attack the patient.
The researchers extracted stem cells from the blood of donors who had been primed with hormones to produce these cells prodigiously. To lessen the risk of graft-versus-host disease, the technique also removes the donor's immune T cells.
Of 43 terminally ill leukemia patients treated with this procedure, 12 survived and were healthy 18 months after the stem-cell transplant, says study coauthor Yair Reisner of the Weizmann Institute in Rehovot, Israel. The other patients died or suffered a relapse of leukemia.
"For patients who don't have matched donors or don't have time to wait, this is a huge step forward," says LeeAnn T. Jensen of the National Heart, Lung, and Blood Institute in Bethesda, Md.
At the core of the mismatch problem are human leukocyte antigens, cell-surface proteins that help direct immune system functions. Genes encoding these proteins are inherited as a unit, one from each parent. Identifying the DNA sequence at three specific locations on each unit provides the six genetic markers used in seeking a match.
Less than a third of patients have a family member who matches five or six markers, but everyone's parents and most siblings match at least three. "It would be very unusual that you wouldn't have a related donor for every patient," Reisner says.
61. To beat leukemia, it helps to be lucky because__________.
A) the patient can not choose an appropriate bone marrow from a tissue bank.
B) the best available transplant contains only three or four correct genetic markers.
C) the patient has a limited range of genetic markers
D) bone marrow transplants are randomized
62. According to the researchers in Israel and Italy, the donated cells can overcome rejection _________.
A) by conquering the recipient’s remaining immune cells.
B) by matching exactly the recipients immune cells.
C) by expanding the options for transplants
D) by building up their dosage.
63. In which of the following are the donated stem cells important to the recipient?
A) Radiation treatment
B) Quantity of cells
C)Related sources
D) Amount
64.As Jensen implies, patients having no matched donors or no time to wait can bear hope of life ________
A) with stem-cell transplant
B) with radiation treatment and chemotherapy
C) by using drugs to suppress immune rejection.
D)by lessening the risk of graft-versus-host disease
65.The message of the passage is clear that stem cell transplants can make it easy for a leukemia patient _______.
A) to survive the disease
B) to find a related donor
C) to match five or six markers.
D)To ward off the procedures to suppress immune rejection.
Part IV Translation ( 20 points )
Directions: Translate the underlined parts in each sentence into Chinese
1. Georgetown University Hospital offers a variety of medical facilities through its many clinical departments. There are, for example, departments of general medicine, pediatrics, surgery, ophthalmology, and obstetrics and gynecology.
2. Although essential hypertension is the etiologic category in the vast majority of cases, it is possible that as many as 5% of hypertensive individuals suffer from the renal arterial diseases.
3. Independently, several groups developed methods to close congenital cardiac defects with devices delivered by catheters.
4. Glomerular filtration rate, urine flow rate and urinary concentrating ability all correlated inversely with the degree ofmedullary hyperemia.
5. Davidson and colleagues strongly suggest that assays of hemoglobin glycosylation should be the diagnostic criterion standard for diabetes.
6. The reversible airway obstruction is caused by smooth muscle contraction and mucosal edema.
7. Individuals infected with large burdens or particularly virulent strains of H pylori may be capable of developing ulcers regardless of their psychological characteristics.
8. Cancer risk is increased with most types of immune deficiency, including congenital disorders and iatrogenic treatments to prevent allograft rejection.
9. Other complications are associated with ischaemia of the tracheal mucosa leading to tracheo-oesophageal fistula, erosion of the innominate artery or, much later tracheal stenosis.
10. A meta-analysis of 22 placebo-controlled hypnotic trials concluded that benzodiazepines and zolpidem produced improvements in sleep latency, total sleep time and sleep quality.
Answer Sheet
Part IV Translation ( 20 points )
1. _____________________, _______________________
2. _____________________,________________________
3. _____________________
4. _____________________,_________________________
5. _____________________
6. _____________________,_________________________
7. _____________________
8. _____________________,_________________________
9. _____________________,_________________________
10. _____________________
Key ( A )
Part I Listening Comprehension ( 10% )
1----5 CDCCB 6-----10 CADAD
11----15 ACABD 16----20 DCACB
Part II Vocabulary ( 20% )
21----25 BCACC 26----30 CDDCC
31----35 ACACA 36----40 ADBCC
Part III Reading Comprehension ( 50% )
41----45 BCACD 46----50 BDCCB
51----55 BDACD
56----60 BDCDD 61----65 BADAB
Part IV Translation ( 20% )
1. 内科，妇产科
2. 原发性高血压，肾动脉疾病
3. 先天性心脏缺损
4. 肾小球滤过率，髓质充血
5. 糖化血红蛋白测定
6. 可逆性气道阻塞，黏膜水肿
7. 致病力强的幽门螺杆菌菌株
8. 免疫缺陷，同种异体移植排斥
9. 气管食管篓，气管狭窄
10. 安慰剂对照安眠药物试验