Unit2 AAmerica is experiencing a major epidemic today.現(xiàn)今美國正在經(jīng)歷一場重要的流行病。Unlike epidemics of the past, it is not a disease transmitted by bacteria or viruses.不同于過去的流行病，它不是由細菌或病毒傳染的疾病。This epidemic is an increase in diseases and problems related to stress, and it touches all of our lives.這個流行病的增加是與壓力有關(guān)的疾病和問題引起的，它涉及我們生活的方方面面。In 1900 the average life expectancy in this country was 47, and the major killer diseases included tuberculosis pneumonia,influenza, cholera, typhoid, and smallpox infectious diseases which struck people of all ages, regardless of their lifestyle.1900年，這個國家的平均預(yù)期壽命為47歲，其主要致命疾病包括肺結(jié)核肺炎，流行性感冒，霍亂，傷寒，天花-這些傳染性疾病襲擊了所有年齡層的人，不管他們的生活方式怎樣。Today, on the other hand, life expectancy has been extended to 74, thanks in large part to the conquest of the acute infectious disease through improved sanitation, better distribution and storage of foods, and the introduction of immunization and antibiotics.如今，在另一方面，預(yù)期壽命已延長至74歲，這在很大程度上是由于對于急性傳染病的征服，通過改善衛(wèi)生條件，更好地分配和儲存食物，以及引進免疫方法和抗生素。 People today are dying of different diseases than they did at the turn of the 20th century, and the principal causes of death today are heart disease, stroke, cancer, cirrhosis of the liver, and diabetes.當(dāng)今人們死于的疾病與20世紀(jì)初不同，現(xiàn)在死亡的主要原因是心臟病，中風(fēng)，癌癥，肝硬化，糖尿病等。These noninfectious, chronic diseases have been shown to be directly related to the way we live, and one of the dominant factors in their development is stressan element of modern life which is taking an increasing toll on our physical and mental well-being.這些非傳染性，慢性疾病已被證明是與我們的生活方式有直接聯(lián)系的，使其發(fā)展的主要因素之一是壓力這一現(xiàn)代生活元素，正對我們的身體和精神健康造成越來越嚴(yán)重的危害。Technically speaking, stress is a physiological state of the body, a state of arousal in response to a perceived danger or threat.從技術(shù)上來說，壓力是機體對感知到的危險或威脅反應(yīng)而表現(xiàn)的一種生理性興奮狀態(tài)。We are all familiar with the physical signs and symptoms of the stress state.我們都熟悉壓力狀態(tài)下的身體信號和癥狀。Think about how you felt that last time you had to swerve to avoid a collision which driving: your heart raced, your palms became sweaty, your muscles tensed, and your stomach knotted.想想你上一次在駕駛時突然轉(zhuǎn)向以避免碰撞是何感覺：你的心狂跳起來，你的手掌變得多汗，你的肌肉緊張，而你的心也揪在一起了。Such a combination of sensations is the result of a complex physical chain reaction which occurs in your body in response to a threat.這種感覺的結(jié)合是一個復(fù)雜的身體連鎖反應(yīng)的結(jié)果，出現(xiàn)在你的身體對威脅做出反應(yīng)的時候。These changes are universal and predictable, and they happen to everyone.這些變化是普遍的并且可以預(yù)見的，可以發(fā)生在每一個人身上。Our prehistoric ancestors, upon encountering a dangerous animal in the wild, would have felt exactly the same response as their bodies switched into a stress-induced “high-gear” to deal with the emergency.我們的史前祖先，一旦在野外意外地遇見危險動物，就會感受到完全一樣的反應(yīng)，當(dāng)他們的身體轉(zhuǎn)入一種緊張引起的“高速擋”，以應(yīng)對緊急狀況。Physiologist Walter Cannon, back in the 1920s, labeled this reaction the fight-or-flight response.生理學(xué)家沃爾特坎農(nóng)，追溯到20世紀(jì)20年代，把這種反應(yīng)稱為打或逃跑反應(yīng)。As the term implies, the original purpose of the fight-or-flight response was to prepare the body to respond either by fighting the enemy, or by fleeing.這個術(shù)語暗示，戰(zhàn)或逃跑反應(yīng)的最初目的是準(zhǔn)備讓身體作出反應(yīng)，要么對抗敵人，要么逃離。Whether the primitive hunter succeeded in killing the mountain lion or in running away from it, the result was the same: once the threat was resolved, the body could relax, eventually returning to its normal baseline functioning.無論是成功殺死美洲獅或遠離它的原始獵人，其結(jié)果是一樣的：一旦威脅得到解決，身體能放松，最終恢復(fù)到自身正常的基礎(chǔ)運作狀態(tài)。Interestingly enough, situations which provoke the fight-or-flight response are not necessarily unpleasant ones.非常有趣的是，引起戰(zhàn)或逃跑反應(yīng)的情況發(fā)生并不必然是不愉快的。Pleasant experiences, if they are sufficiently intense, can produce the same combination of physiological symptoms.愉快的經(jīng)驗，如果它們足夠的強烈，可以產(chǎn)生相同組合的生理癥狀。When your boss tells you that hes recommended you for a promotion, you are most likely experiencing some of the same physiological responses that you experience when you swerve to avoid a traffic accident: sweaty palms, racing heart, changes in breathing.當(dāng)你的老板告訴你，他已經(jīng)推薦你晉升，你是最有可能體驗到一些與當(dāng)你拐彎去避免一宗交通意外所產(chǎn)生的相同的生理反應(yīng)：手心出汗，心跳加速，呼吸的變化。Pleasant or unpleasant, its the intensity of the experience that produces the stress.愉快或不愉快的，取決于產(chǎn)生壓力的感覺的強度。Dr. Hans Selye, an endocrinologist whose ground-breaking research was a major contribution to our understanding of stress, defined stress as the nonspecific or general response of the body to any demand made upon it to readjust.漢斯薛利醫(yī)生，一名內(nèi)分泌學(xué)家，其開創(chuàng)性研究在我們對壓力的理解上是一個重大的貢獻，把壓力定義為身體根據(jù)它的任何需要作出重新調(diào)整的非特異性或一般應(yīng)激反應(yīng)。Selye emphasized that stress is not necessarily something to be avoided.薛利強調(diào)，壓力是不可避免的。It is a natural part of our lives; any normal activity, pleasant or unpleasant, produces some degree of stress.它是我們生命自然的一部分，任何正?；顒?，愉快或不愉快，都會產(chǎn)生一些程度的壓力。As Selye said “The absence of stress is death.”正如薛利說的：“沒有壓力是死亡。Just as stress prepared primitive man to confront the fight with his enemy or to run away, so in modern life it helps the athlete to achieve peak performance or the executive to meet impossible deadlines.“正像原始人因壓力做好面對敵人是斗爭或是逃跑的準(zhǔn)備一樣，在現(xiàn)代生活中它也可以幫助運動員達到最佳表現(xiàn)或主管人員處理不可能的最后期限。Under such circumstances, stress can be a very useful response, contributing to heightened achievement and a greater sense of personal satisfaction.在這種情況下，壓力可以是一個非常有用的反應(yīng)，有助于提高成績和個人滿足感。When stress is associated with such a positive experience, Selye called it eustress (something also called prostress); when it becomes unpleasant or damaging, it is called distress.當(dāng)這種壓力是與一種積極的經(jīng)驗有聯(lián)系時，薛利稱之為好的壓力（也被稱為積極壓力），當(dāng)它變得不愉快或具破壞性時，它被稱為不好的壓力。Eventsthat provoke stress are known asstressors.引起壓力的事件被稱為壓力源。Its easy to identify many such triggers of stress in our daily lives.在我們的日常生活中，識別許多這樣的壓力源是容易的。Some sources of stress can be classified as environmental: weather changes, temperature, noise, air pollution, crowding, and uncomfortable living or work space can all have an influence on your stress level.有些壓力源同環(huán)境一樣可被歸類為：天氣變化，溫度，噪音，空氣污染，擁擠和不舒服的生活或工作空間，都可以對你的壓力水平造成影響。A major source of stress in our modern world is change; more than ever before in history we are forced constantly to adapt to rapid change in many important aspects of our liveschanging values, family structure, and sex roles, the decline of religious faith, and the changing nature of work.在我們現(xiàn)代世界的一個主要壓力來源是變化，我們比過去任何時候更加被迫地去不斷適應(yīng)生活中許多重要方面的快速變化價值觀改變，家庭結(jié)構(gòu)，性別角色，宗教信仰的減弱，和工作性質(zhì)的變化。Interpersonal stressors emerge from your relationships with other peopleyour boss, your fellow workers, your family and friends.人際關(guān)系的壓力源來自你同別人的交往中你的老板，你的同事，你的家人和朋友們。And a significant source of stress in many of our lives today is work stressorsthe structure of your employers organization, your position within it, your interaction with other people, and your feelings about job are all factors that can contribute to raising your overall stress level.今天我們生活中很明顯的一個壓力源來自工作你所在單位的機構(gòu)組成，你在其中的職位，你與其他人互動，你對工作的感受都是能提高你的總體壓力水平的因素。You may have notice that many of the stressors we have been describing dont actually represent threats to your physical survival.你可能已經(jīng)注意到許多我們描述的壓力源事實上并不代表會威脅你的身體生存。Rather, they are psychological or social in nature.相反地，它們本質(zhì)上是心理或社會性質(zhì)的。Imagined threats to your sell-esteem or security can arouse the fight-or-flight response just as readily as an attacking mountain lion or an oncoming car.想象你的自尊或安全的威脅會激發(fā)戰(zhàn)或逃反應(yīng)，就像面對攻擊性的美洲獅或迎面而來的汽車反應(yīng)一樣。Moreover, our psychological and emotional reactions to stressful situation, such as anxiety or guilt, can actually become potent stressors in their own right.此外，我們心理上和情緒上對有應(yīng)激情況的反應(yīng)，比如焦慮或內(nèi)疚，實際上可以憑借它們本身的能力成為強大的壓力源。What arouse a high level of stress in one person may not be perceived as threatening to another, for our individual perception of the stressor is what ultimately makes the situation stressful or not.能激起一個人高水平的壓力的（事件）可能不被視為能對另一個人構(gòu)成威脅，因為我們個人對壓力的感覺，最終決定了是否產(chǎn)生壓力感We are all different in our biochemical make-up, physical strength, psychological and emotional characteristics, values, attitudes, habits, and social roles.我們在我們的生化結(jié)構(gòu)，體力，心理和情感特征，價值觀，態(tài)度，習(xí)慣和社會角色上都是不一樣的。And all these factors influence our interpretation of events and, therefore, the way we respond physically and psychologically to them.而所有這些因素影響我們對事件的理解，因此，也決定了我們對他們作出的生理和心理上的反應(yīng)。As a primitive survival mechanism, the fight-or flight response served our ancestors well as a means of mobilizing the bodys defenses in times of emergency.作為一種原始的生存機制，戰(zhàn)或逃跑反應(yīng)為我們祖先在緊急情況下及時動員身體防御服務(wù)很好。Why, then, has stress become such a problem in modern life?為什么，隨后，在現(xiàn)代生活中壓力會變成一個難題呢？In the case of the primitive hunter, once the danger had been dealt with by fighting or fleeing, the problem was resolved and the stress was relieved.就原始獵人來說，一旦通過戰(zhàn)或逃跑使危險得到了處理，問題解決了，壓力才會被緩解。However, if we look around us today, we notice that the options of fighting or fleeing are rarely appropriate in our modern world.但是，今天如果我們回過頭來看今天，我們注意到當(dāng)今現(xiàn)代社會戰(zhàn)或逃跑的選擇很少是合適的。For example, if you have an argument with your boss, you may feel all the symptoms of stress but you cant relieve your stress by striking out at him, nor would it do to run away.例如，如果你和你的老板發(fā)生爭論，你可能會感到壓力所有的癥狀 - 但你不能通過揍他一頓來減輕你的壓力，也不會逃跑。And so the level of anger and arousal persists in the absence of a socially acceptable outlet, and at the end of the confrontation you still feel as if you want to fight someone or run away.所以氣憤和激發(fā)的興奮狀態(tài)在現(xiàn)實社會中缺乏得到合理的發(fā)泄途徑，最后你仍覺得好像你想和人打架或逃跑。The fight-or flight response has now become an internalized feeling that you carry about with you, like a ticking time bomb.戰(zhàn)或逃跑反應(yīng)現(xiàn)在已經(jīng)變成了隨時隨地的一種內(nèi)在感覺，就像你隨身攜帶一個開始倒計時的定時炸彈。If the fight-or flight response is activated without being used to its intended purpose, it can become a major source of distress.如果戰(zhàn)或逃跑反應(yīng)沒有被用于其預(yù)期目標(biāo)的激活，它可以成為不好的壓力的主要來源。If it is fired off too often, or persists too long, the body will remain in a state of continual alarm or mobilization，and the potent hormones released in the stress response can actually damage the bodys vital organs, nervous system, and immune mechanisms.如果它被激發(fā)過于頻繁，或持續(xù)時間過長，身體會留在一個不斷報警或調(diào)節(jié)的狀態(tài)，壓力反應(yīng)中大量釋放的激素實際上可以破壞人體的重要器官，神經(jīng)系統(tǒng)，和免疫系統(tǒng)。Ironically, it appears that the stress response, which was a vital survival mechanism for our remote ancestors, may in fact be killing us today.諷刺的是，它似乎是我們的遠古祖先生存的重要機制的應(yīng)激反應(yīng)，實際上現(xiàn)今可能殺死我們。Before it kills us in the end, stress can make us fat.在它最終殺死我們之前，壓力可以使我們發(fā)胖。Unit3aAntibiotics are nonrenewable resources.抗生素是不可再生的資源。 In the past we have managed to develop new antibiotics to replace those that had become ineffective, but that has changed now that some bacteria have become resistant to all available drug treatments.在過去，我們設(shè)法去開發(fā)新的抗生素，以取代那些已變得無效的抗生素，但那種情況已經(jīng)變了，由于一些細菌對所有可用的藥物治療已具耐藥性。Until recently infections caused by multi-resistant Staphylococcus aureus (MRSA), which is common in most hospitals, could be treated using vancomycin.直到最近多重耐藥金黃色葡萄球菌（MRSA）所引起的感染，這是大部分醫(yī)院常見的感染，可使用萬古霉素治療。Compared with many other bacteria, S.aureus is a very virulent or aggressive bacterium and can produce life-threatening infections.與許多其他細菌相比，金黃色葡萄球菌是種有劇毒或具有攻擊性的細菌，并且能夠產(chǎn)生致命的感染。In Japan and the US, strains resistant to vancomycin have been found, placing a death sentence on patient with these infections.在日本和美國，對萬古霉素抗藥的菌株已經(jīng)被發(fā)現(xiàn)，這是對這些感染病人判死刑。Antibiotic resistance is not only confined to hospitals; multi-resistant strains of Golden Staph are now appearing in the Australian community.抗生素耐藥性不僅局限于醫(yī)院;金黃色葡萄球菌多重耐藥菌株現(xiàn)已在澳大利亞社區(qū)出現(xiàn)。These strains, unlike their hospital-based cousins, usually remain sensitive to agents such as erythromycin and tetracycline.不像它們在醫(yī)院里的同類菌株，這些菌株通常對藥劑保持敏感，如紅霉素和四環(huán)素。However, this was also the case for the MRSA strains in hospitals 10-15 years ago.不過，這也是10-15年前醫(yī)院里MRSA菌株的情況。One approach would be to treat all cases of Golden Staph infection with vancomycin.萬古霉素的使用可治療所有感染金黃色葡萄球菌的病例。The problem with this tactic is that it would increase the likelihood of resistance to this drug of last resort.這種方法的問題所在是，它將增加對這最后一招的藥物耐藥的可能性。We are safe while these bacteria remain sensitive to erythromycin or tetracycline but, given the experience with their hospital-based cousins, it will only be a matter of time before these become ineffective too.在這些細菌對紅霉素或四環(huán)素仍然敏感的時候，我們是安全的，但是，考慮到它們在醫(yī)院里的同類菌株的經(jīng)驗，在這些藥物也變得無效之前這將只是一個時間上的問題。There are other examples of life-threatening infections that are resistant to multiple antibiotics.還有其他對多種抗生素耐藥的致命感染的例子。One of these is tuberculosis, with multi-resistant strains of TB common in many countries.其中之一是肺結(jié)核，它以多耐藥結(jié)核菌株常見于許多國家。Because of the migration patterns and travel of people around the world, these strains can easily be introduced into other countries.由于移民的情況與世界各地的人們的旅游，這些菌株可以很容易地被引入到其他國家。At present many of these bacteria are still treatable but more toxic drugs are needed and treatment takes longer.目前許多這些細菌仍是可處理的，但需要更多有毒的藥品和延長了治療時間。In the US, outbreaks of multi-resistant strains have occurred in both health settings and prisons, causing the deaths of many who came into contact with the original infected person.在美國，出現(xiàn)在健康環(huán)境和監(jiān)獄的多耐藥菌株的疫情爆發(fā)，造成很多與接觸到最初的感染者的人的死亡。COMMON BACTERIA.常見的細菌。Respiratory tract infectionsparticularly pneumonia, middle ear infections and sinusitisare often caused by Streptococcus pneumoniae.呼吸道感染尤其是肺炎，中耳炎，竇炎通常是由肺炎鏈球菌引起的。This organism is also a common cause of bacterial meningitis.這種微生物也是一種細菌性腦膜炎的常見病因。Since the late 1980s we have seen an exponential rate of increase in the antibiotic resistance of this organism.20世紀(jì)80年代末以來，我們已經(jīng)經(jīng)歷了這種微生物的抗生素耐藥呈指數(shù)的速度增長。In the late 1980s, approximately 1% of these isolates in Australia were resistant to penicillin.在20世紀(jì)80年代末，在澳大利亞大約1的這種分離菌株對青霉素耐藥。In a study performed a few years ago, the rate of resistance had risen to 7% and more recently the rate of resistance appears to have been growing at about 20%.在幾年前完成的一項研究中顯示，耐藥率已經(jīng)上升到7，而且較近期的耐藥率似乎已在以約20的速度增長。This rising resistance has particular relevance for meningitis, which was uniformly fatal in the pre-antibiotic era.這上升的耐藥性對腦膜炎有特殊的相關(guān)性，腦膜炎在前抗生素時代是一律致命的。Antibiotics have made a huge difference to this condition, but we are now getting to the stage where we no longer have effective and proven therapy that works against some of these higher level resistance strains.抗生素對這種情況起到了巨大的作用，但我們現(xiàn)在進入了不再有抵抗這些高濃度耐藥株有效的和已經(jīng)被證明的治療方法的階段。If early treatment doesnt occur, patients can be left with profound problems such as neurological impairment or deafness.如果早期治療不被發(fā)現(xiàn)，患者可遺留下嚴(yán)重問題，如神經(jīng)損傷或失聰。NEW RESEARCH.新的研究。Bacteria continually develop resistance to antibiotics.細菌不斷發(fā)展對抗生素耐藥性。It is therefore essential that there should be ongoing research and development so new antibiotics are developed.因此，必須要有不間斷的研制和開發(fā)，從而開發(fā)新的抗生素。To be successful in our treatment of bacterial infections in the future we will need to design completely new classes of antibiotics.將來要在我們的細菌性感染治療上取得成功，我們將需要設(shè)計全新種類的抗生素。We need the equivalent of the discovery of penicillin by Fleming and its development by Florey to be repeated every 10-20 years if we want to keep ahead of bacterial infections.如果我們想要在細菌感染面前保持領(lǐng)先，我們需重復(fù)地每隔10-20年就得有相當(dāng)于由弗萊明發(fā)現(xiàn)的并由弗洛里開發(fā)的青霉素的等同物。New antibiotic development has slowed down for many reasons.新抗生素的研發(fā)速度因很多原因而放慢了。There are huge costs involved in developing and marketing antibiotics.有關(guān)抗生素的開發(fā)和營銷需要巨額費用。It is estimated that at present it costs about US$300 million per new compound released on the international markets.據(jù)估計，目前在國際市場上每推出一種新藥約耗費300美元。This means that a drug has to look very promising before pharmaceutical companies will invest such huge amounts.這意味著，在制藥公司將投資如此巨大的數(shù)額之前該藥必須能看得到相當(dāng)有前景。In addition to the development costs, there has been general complacency on the part of the community, medical profession and pharmaceutical industry during the 1980s.除了開發(fā)成本，在20世紀(jì)80年代期間，社會，醫(yī)療職業(yè)和制藥工業(yè)各界普遍出現(xiàn)自滿。At that time, infectious diseases appeared to be under control with the available antibiotics.當(dāng)時，傳染性疾病似乎是用有效的抗生素控制住了。Many pharmaceutical companies lowered the emphasis on new drug development for antibiotics and in some cases left the field altogether.許多制藥公司降低新抗生素藥物開發(fā)的重視，并在某些情況下一起離開這個領(lǐng)域。While research and development have been winding back, the pace of bacterial adaptability has been accelerating.在研究及開發(fā)一直在倒退的時候，細菌的適應(yīng)力的步伐一直在加速。Previously, most of the antibiotic resistance was due to the breakdown of the drug by bacterial enzymes.以前，大多數(shù)的抗生素耐藥是由于細菌的酶對該藥物的分解。An example is the breakdown of penicillin by the beta-lactamase enzyme.一個例子是-內(nèi)酰胺酶對青霉素的的分解。We overcame this problem by developing enhanced antibiotics from existing products, chemically engineering them so that they were resistant to these enzymes.我們通過從現(xiàn)有產(chǎn)品開發(fā)增強抗生素來克服了這個問題，通過用化學(xué)方法設(shè)計增強抗生素而使它們抵抗這些酶。However, the bacteria adapted to this change.然而，細菌適應(yīng)了這種改變。Usually, antibiotics recognize and attack a particular site on the bacteria.通常情況下，抗生素識別和攻擊細菌上特定的位置。However, the bacteria modified these target sites so that the antibiotics could not lock onto the bacteria.但是，細菌修正了這些目標(biāo)位置以致抗生素?zé)o法鎖定細菌。This is analogous to the bacteria moving the goal posts.這是類似于細菌改變目標(biāo)靶點的位置。Therefore, even though the antibiotics were no longer destroyed by the bacterial enzymes they now had no site on which to act.因此，即使抗生素不再被細菌酶破壞，它們現(xiàn)在已經(jīng)沒有作用的位置。COMMUNITY OVERUSE.社區(qū)過度使用。The total tonnage use of antibiotics in the general community is also a problem.抗生素使用的總噸數(shù)在整個社區(qū)的也是一個問題。We are frequently using antibiotics when they are unlikely to give any benefit, such as the treatment of viral respiratory tract infections.我們在抗生素不太能給任何益處的時候仍頻繁使用抗生素，如病毒性呼吸道感染的治療。We are, however, also using antibiotics in ways that appear to be wasteful of this precious resource.可是，我們似乎也是采用對這一寶貴資源的浪費的方式使用抗生素。Large amounts of antibiotics are used in animals as growth promoters.大量的抗生素是用來作為動物助長劑。While there are commercial and economic benefits to this, the cost in the form of antibiotic resistance is high.雖然對于這一點具有商業(yè)和經(jīng)濟利益，但抗生素抗藥性的形成所付出的代價是高的。Vancomycin-resistant enterococcus is thought to have developed from t