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  3. The complications frequently accompanying diabetes, such as impairment of vision and of kidney function, are now thought to resu

The complications frequently accompanying diabetes, such as impairment of vision and of kidney function, are now thought to resu

admin2014-12-26  59
问题     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 meagre, 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.
According to the text, widely spaced doses of insulin can cause______.
选项 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
答案C
解析 细节题。根据insulin、doses可定位到第一段But the diabetic generally receives only one large dose daily．The diabetic’s blood glucose concentration can thusfluctuate 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)．”但是糖尿病患者一般是每天得到一次大剂量胰岛素的注射。这样在两次注射之间，糖尿病患者的血糖浓度会发生很大波动，而且目前已被指出，并发症可能就是源于这些高血糖浓度时期(高血糖)。”说明两次注射之间糖尿病患者的血糖浓度会发生剧烈的变化，和C选项内容一致，其中radical changes和原文fluctuate greatly为同义转换，所以答案选C。
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