SAMPLE 19

　　[醫(yī)學(xué)類]

　　The complications frequently accompanying diabetes, such as impairment of vision and of kidney function, are now thought to result from the lack of continuous control of blood glucose concentrations. The healthy pancreas, in response to increases in blood glucose concentration, releases small quantities of insulin throughout the day and thereby maintains the concentration within physiological limits (nomoglycemia). But the diabetic generally receives only one large dose daily. The diabetic’s blood glucose concentration can thus fluctuate greatly during the interval between doses, and it has been suggested that the complication result from the periods of high concentrations of blood glucose (hyperglycemia). Many investigators thus believe that restoration of normoglycemia might halt the progression of such complications and perhaps even reverse them.

　　There are three primary techniques that have been investigated for restoration of normoglycemia. They are: transplantation of whole, healthy pancreases; transplantation of islets of Langerthan, that portion of the pancreas that actually secretes insulin, and implantation of artificial pancreases. There has, in fact been a great deal of success in the development of these techniques and each seems, on the whole, promising. Nonetheless, it will undoubtedly be many years before any one of them is accepted as a treatment for diabetes.

　　To many people, the obvious approach would seem to be simply to transplant pancreases from cadavers in the same manner that kidneys and other organs are routinely transplanted. That was the rationale in 1966 when the first recorded pancreas was performed. Between 1960 and 1975, there were forty-six pancreas transplants in forty-five other patients in the United States and five other countries. But only one of these patients is still alive with a functioning graft and surgeons have found that the procedure is not simple as they once thought.

　　The surviving patient has required no insulin since the operation. Another patient survived 638 days without requiring insulin. And one patient survived a transplantation for more than a year, but died when he chose not to take immunosuppressive drugs. These results, though meager, suggest that the procedure has the potential for success.

　　The rest of the patients, however, either rejected the transplant or died within a short period. There does not appear to be any technical problem with the procedure. Rather, most of the patients were already so severely debilitated by the complications of diabetes that they could not withstand the surgery and the immunosuppressive regimen required to prevent rejection. More than half of the patients, furthermore, also required a kidney transplant. Most investigators now agree that the simultaneous transplantation of both organs is too great a shock to the patient and greatly increases the total risk.

　　1. Which of the following best states one of the main conclusions of the text?

　　[A] Although the techniques for pancreas transplants appear to be theoretically correct, there are problems that must be solved before the operation can be used as a treatment for diabetes.

　　[B] Although the techniques for pancreas transplants are still being developed, the experimental results show that the operation will be a successful treatment for diabetes in the near future.

　　[C] Although pancreas transplants are reliable, many diabetics are reluctant to undergo the operation because of the side effects of immunosuppressive drugs.

　　[D] Although pancreas transplants alone are not generally successful, the operation can be used in conjunction with other procedures to treat diabetes.

　　2. According to the text, widely spaced doses of insulin can cause

　　[A] reversal of normal kidney function.

　　[B] delay in the onset of diabetes.

　　[C] radical changes in the concentration of blood glucose.

　　[D] restoration of normoglycemia.

　　3. According to the text, a periodic high concentration of blood glucose in diabetics is a possible cause of

　　[A] deterioration of the pancreas.

　　[B] damage to the eyes and kidneys.

　　[C] rejection of transplanted organs.

　　[D] inadequate secretion of insulin.

　　4. It can be inferred from the text that one of the important contributing causes of the failure of most pancreas transplants has been the

　　[A] reluctance of patients to cooperate with physicians.

　　[B] imperfect techniques used in the operation.

　　[C] scarcity of immunosuppressive drugs.

　　[D] weakened condition of the patients.

　　5. The text suggests that the author considers the data concerning the success of pancreas transplants to be

　　[A] invalid.

　　[B] indirect.

　　[C] inaccurate.

　　[D] insufficient.
　　[答案與考點解析]

　　1. 【答案】A

　　【考點解析】本題是一道審題定位題。本題的題干比較奇怪，沒有明確指出本題答案信息在原文中的確切位置。在大多數(shù)情況下，考生會迷失解題思路。我們一再重申：考生在迷失解題思路時一定要多想一想全文的中心主旨句，以及各段的主題句。本文的中心主旨句是第二段的尾句，本題的正確選項A恰恰是來自于本句。這再次說明我們在迷失解題思路時應(yīng)該首先想到全文的中心主旨句或每段的主題句。

　　2. 【答案】C

　　【考點解析】這是一道細節(jié)推導(dǎo)題。通過本題題干中的“widely spaced doses of insulin”可將本題的答案信息來源確定在首段的第三、四句。因為這兩句話提到了“doses of insulin”。通過仔細閱讀和理解第三、四句，就可推導(dǎo)出本題的正確選項C�？忌�在解題時一定要善于理解和把握題干和原文所進行的同義詞替換。

　　3. 【答案】B

　　【考點解析】這是一道句間關(guān)系題。通過題干中的“periodic high concentration”可將本題的答案信息來源迅速確定在第一段的第四句。通過仔細閱讀和理解第四句，尤其是把第四句中的“complication”和第一句中的“complications”進行連貫的理解，就可推導(dǎo)出本題的正確選項B�？忌�在解題時要善于發(fā)現(xiàn)和理解句子之間的關(guān)系。

　　4. 【答案】D

　　【考點解析】這是一道細節(jié)推導(dǎo)題。通過題干中的“failure”一詞可推斷本題的正確答案信息在倒數(shù)第二段尾句的前后，因為該句所談?wù)摰闹行脑掝}是“success”。又根據(jù)題干中的“most”一詞將本題的答案信息確定在尾段的第三句，因為該句中含有“most”一詞。通過閱讀和理解尾段第三句，可推導(dǎo)出本題的正確答案是D�？忌�在解題時要注意靈活理解題干和原文所表達的內(nèi)容，千萬不能生硬地進行理解。

　　5. 【答案】D

　　【考點解析】本文是一道詞匯理解題。本題題干中的“success”將本題的答案信息來源確定在倒數(shù)第二段的尾句。該句中的“meager”(不足的，貧乏的)暗示本題的正確選項是D�？忌�在解題時一定要對關(guān)鍵詞加以重視并進行合理的推斷。

　　[參考譯文]

　　通常與糖尿病相伴的并發(fā)癥，如視力和腎功能的損害，現(xiàn)在被認為是由于無法連續(xù)控制血液中的葡萄糖濃度所導(dǎo)致的。健康的胰臟，在血糖濃度增加時，會在整個白天不斷地釋放出少量的胰島素，從而使血糖濃度維持在生理限度之內(nèi)(正常血糖量)。但是糖尿病患者一般是每天得到一次大劑量胰島素的注射。這樣在兩次注射之間，糖尿病患者的血糖濃度會發(fā)生很大波動，而且目前已被指出，并發(fā)癥可能就是源于這些高血糖濃度時期(高血糖)。因此，許多研究人員相信，恢復(fù)正常的血糖濃度或許能阻止這些并發(fā)癥的發(fā)展，并進而可能減輕并發(fā)癥。

　　為了恢復(fù)正常的血糖濃度，已對三種主要的技術(shù)進行了研究。它們分別是：健康胰臟的整個移植;胰島部分的移植，胰島是胰腺中實際分泌胰島素的部分;以及人造腺的移植。事實上，這些技術(shù)的發(fā)展都獲得了成功，而且從整體上講，每種技術(shù)都大有希望。然而，毫無疑問地，在任何一種技術(shù)被接受用作糖尿病患者的治療手段之前，還會有很多年的時間。

　　對多數(shù)人而言，顯而易見的方法看來可能是從尸體中移植胰腺，就象移植腎臟和其它器官那樣。這便是1966年第一例胰腺移植手術(shù)的理論基礎(chǔ)。在1966年至1975年間，在美國和另外五個國家，共有45名其它病人進行了46例胰腺移植手術(shù)。但目前，只有其中一個病人尚在人世，而且移植的胰腺功能健全。因此，手術(shù)醫(yī)生們發(fā)現(xiàn)，手術(shù)過程并不像他們先前想象的那么簡單。

　　幸存的病人從那次手術(shù)之后不再需要注射胰島素。另一個病人在不需要注射胰島素的情況下活了638天。還有一名病人在移植之后存活了一年，但他決定不服用免疫藥物之后就死去了。這些結(jié)果，盡管為數(shù)不多，可也表明了手術(shù)過程有潛在成功的可能。

　　然而，其余的病人或者出現(xiàn)排異反應(yīng)，或者在很短一段時期后死去。在手術(shù)過程中，看起來是不存在任何技術(shù)問題的。不過，大多數(shù)的病人都由于糖尿病的并發(fā)病已經(jīng)很衰弱，以至于無法經(jīng)受手術(shù)和為防止排異反應(yīng)所需的免疫抑制療程。另外，一大半病人還需要進行腎臟移植。目前，多數(shù)研究人員都認為同時移植兩個器官對病人自身系統(tǒng)影響太大，而且極大地增加了整體的風(fēng)險。