生物医学工程类英中对照格式

The biologically determined duration of human life should beyond doubt be at least 110 years; some data suggest it should be 150 years. In reality though, the mean duration of human life does not reach even the middle of this span. Whether there has ever been that “golden age” of humankind when, as told by the Biblical sources, people did reach that age – it is hard to tell. The 80-year mark is not reached by 65% of people, 90% do not reach 90 years, and only a few live beyond their centenary. Even if human beings avoid illness and injury in their whole life, they still inevitably die because of “old age”. But why, in some cases, this “old age” takes 60-year-olds, while in other cases, it spares 90-year-olds? What is the basis of ageing?

Many authors addressing these questions only point at life-long contamination of the body, its self-intoxication as it we

re. But what are the mechanisms of the subsequent disorders? What does the immune system do – our principal guardian of Health that is closely linked to the quality of life?

Indeed, ageing is accompanied by certain changes in the immune system among others. They affect all of its components: stem cells, Т- and B-lymphocytes, macrophages. Since early childhood, the “thymic clock” starts to gradually slow down, which is observed as the lower proliferative activity of Т-cells; their worsening effector and helper functions make one susceptible to infections and malignancies (their rates are known to be age-related). An old person is indeed i

ncreasingly vulnerable to infections, which become to be among the principal direct causes of death. Respiratory infections and pyelonephritis are particularly frequent. With advancing age, higher rates are seen also for a number of other diseases, such as cardiovascular pathology, tumours, diabetes, and dementia. These changes taking place in the body are often called “age-related” or “normal for this age”.

Immunodeficiency implies a less strict control of abnormal mitoses, cell divisions and formation of tumour cells. They occur in the body on a constant basis and quite frequently at that; however, possessing a foreign antigenic structure, they immediately are “spotted” by the immune guardians and exterminated on the spot. I

f these guardians “miss” them the moment they appear and fail to exterminate them on time, their antigenic structure is recognized as “own” not before long, and, according to fundamental biological principles, the production of these antibodies is blocked. The outcome of this body-tumour fighting becomes predetermined.

毫无疑问，生物学决定的人类寿命至少可以达到110年;部分资料表明应为150年。但实际上，人类平均寿命甚至还未达到这种时间跨度的一半。如圣经原始资料所述，人类曾经达到过这种年龄，但人类是否存在那样的“黄金时代”，则难以说清楚。65%的人们寿命不足80岁，90%的人们不足90岁，仅有很少的人们能够长逾百岁。即使人的一生能够避免疾病和伤害，仍不可避免地因“老年”而去世。但是，为什么在某些情况下60岁即已称为“老年”，而在其他情况下其可以延长到90岁呢?年龄

老化的基础是什么?

许多作者将这些问题的答案指向了人体的终生污染，即自我中毒。但随后的紊乱机制是什么呢?与我们生命质量密切相关的主要健康卫士 – 免疫系统的作用是什么?

实际上，除其他变化外，年龄老化还伴随着免疫系统的特定变化。这些变化对免疫系统各个组成部分均产生影响：干细胞、Ò- 和B-淋巴细胞、巨噬细胞等。自幼童时期，“胸腺时钟”开始逐步减速，这可以视作 Ò- 细胞增殖活动趋缓;其不断恶化的效应器和助手功能使得人们易患感染和恶性肿瘤(已知其发病率与年龄相关)。老年人确实越来越容易受感染影响，其正在成为导致死亡的主要直接原因之一。呼吸系统感染和肾盂肾炎的发病率尤其频繁。随着年龄的老化，其他许多疾病的发病率也逐步升高，例如心血管病变、肿瘤、糖尿病和痴呆等。人

免疫缺陷意味着对异常有丝分裂、细胞分裂和肿瘤细胞形成的控制力度减弱。他们不断在体内生成，而且生成的频

率较高;但是，由于其携带了外来抗原结构，免疫卫士能够立即“发现”他们，并立即加以消灭。如果这些卫士在其形成时“错过”了他们，则无法按时消灭，他们的抗原结构被视作“自身”不久前形成的，而根据基本的生物学原理，随后不会产生针对他们的抗体。这就预先确定了人体 – 肿瘤抗争的结果。