（新概念第四26课－背景音乐：高飞）

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It is animals and plants which lived in or near water whose remains are most likely to be preserved, for one of the necessary conditions of preservation is quick burial, and it is only in the seas and rivers, and sometimes lakes, where mud and sit have been continuously deposited, that bodies and the can be rapidly covered over and preserved.
But even in the most favourable circumstances only a small fraction of the creatures that die are preserved in this way before decay sets in or, even more likely, before scavengers eat them. After all, all living creatures live by feeding on something else, whether it be plant or animal, dead or alive, and it is only by chance that such a fate is avoided. The remains of plants and animals that lived on land are much more rarely preserved, for there is seldom anything to cover them over. When you think of the innumerable birds that one sees flying bout, not to mention the equally numerous small animals like field mice and voles which you do not see, it is very rarely that one comes across a dead body, except, of course, on the roads. They decompose and are quickly destroyed by the weather or eaten by some other creature.
It is almost always due to some very special circumstances that traces of land animals survive, as by falling into inaccessible caves, or into an ice crevasse, like the Siberian mammoths, when the whole animal is sometimes preserved, as in a refrigerator. This is what happened to the famous Beresovka mammoth which was found preserved and in good condition. In his mouth were the remains of fir trees -- the last meal that he had before he fell into the crevasse and broke his back. The mammoth has now just a suburb of Los Angeles. Apparently what happened was that water collected on these tar pits, and the bigger animals like the elephants ventured out on to the apparently firm surface to drink, and were promptly bogged in the tar. And then, when they were dead, the carnivores, like the sabre-toothed cats and the giant wolves, came out to feed and suffered exactly the same fate. There are also endless numbers of birds in the tar as well.

 

Medical Insight （December 25, 2007）

Self-made Audio Programme 30(本人原声)

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Merry Christmas! Welcome to Medical Insight December 25, 2007, I’m Dr. Alex Roy. This week let’s take a look at Infection in Solid-Organ Transplant Recipients. Increasingly potent immunosuppressive agents have dramatically reduced the incidence of rejection of transplanted organs while increasing patients’ susceptibility to opportunistic infections and cancer. At the same time, patterns of opportunistic infections after transplantation have been altered by routine antimicrobial prophylaxis for Pneumocystis carinii卡氏肺孢子病,

and cytomegalovirus. These patterns have also been altered by the emergence of new clinical syndromes(e.g., polyomavirus多瘤病毒type BK nephropathy) and by infections due to organisms with antimicrobial resistance. Unfortunately, no assays accurately measure a patient’s risk of infection. Currently, therefore, the clinician assesses a recipient’s risk of infection while considering the risk of allograft rejection, the intensity of immunosuppression, and other factors that may contribute to his or her susceptibility to infection. Epidemiologic exposures can be divided into four overlapping categories: donor-derived infections, recipient-derived infections, nosocomial infections, and community infections. Three general preventive strategies are used: vaccination, universal prophylaxis, and preemptive therapy抢先治疗. This article reviews general concepts for the management of transplantation-associated infections and discusses recent advances and challenges.

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Many people in industry and the Services, who have practical experience of noise, regard any investigation of this question as a waste of time; they are not prepared even to admit the possibility that noise affects people. On the other hand, those who dislike noise will sometimes use most inadequate evidence to support their pleas for a quieter society. This is a pity, because noise abatement really is a good cause, and it is likely to be discredited if it gets to be associated with had science.
One allegation often made is that noise produces mental illness. A recent article in a weekly newspaper, for instance, was headed with a striking illustration of a lady in a state of considerable distress, with the caption 'She was yet another victim, reduced to a screaming wreck'. On turning eagerly to the text, one learns that the lady was a typist who found the sound of office typewriters worried her more and more until eventually she had to go into a mental hospital. Now the snag in this sort of anecdote is of course that one merely a symptom? Another patient might equally well complain that her neighbours were combining to slander her and persecute her, and yet one might be cautious about believing this statement.
What is needed in case of noise is a study of large numbers of people living under noisy conditions, to discover whether they are mentally ill more often than other people are. Some time ago the United States Navy, for instance, examined a very large number of men working on aircraft carriers: the study was known as Project Anehin. It can be unpleasant to live even several miles from an aerodrome; if you think what it must be like to share the deck of a ship with several squadrons of jet aircraft, you will realize that a modern navy is a good place to study noise. But neither psychiatric interviews nor objective tests were able to show any effects upon these American sailors. This result merely confirms earlier American and British studies: if there is any effect of noise upon mental health, it must be so small that present methods of psychiatric diagnosis cannot find it. That does not prove that it doesnot exist: but it does mean that noise is less dangerous than, say, being brought up in an orphanage -- which really is mental health hazard.

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Medical Insight （December 17, 2007）

Self-made Audio Programme 30(本人原声)

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Welcome to Medical Insight December 17, 2007, I’m Dr. Alex Roy.

A 44-year-old woman was admitted to the hospital because of generalized, painful, ulcerated cutaneous lesions. 4 years before admission, erosions on the scalp developed, followed by a generalized papular skin eruption. Examination by a dermatologist 2 years later revealed scarring alopecia and multiple hyperkeratotic erythematous plaques on the trunk and arms. Biopsy specimens have been interpreted as squamous-cell carcinoma. She had been treated with topical and systemic agents without much improvement; the lesions seemed to respond to mycophenolate mofetil霉酚酸酯, but after 1 month of treatment, new skin lesions characterized as ulcerated, annular nodules and plaques developed. Laboratory tests disclosed the presence of antinuclear and antiribonucleoprotein antibodies, mild anemia, leukocytosis, and thrombocytosis.

This complex case involving a rare, recently recognized disorder, poses several questions.

First, are there alternative interpretations for the lesions that were diagnosed on biopsy as squamous-cell carcinoma?

Second, do the varied cutaneous manifestations all represent the same process, or are there several processes?

Finally, if there are multiple processes, are they causally related?

Final Diagnosis：Aggressive epidermotropic CD8⁺ cytotoxic cutaneous T-cell lymphoma侵袭性表皮性CD8⁺毒性皮肤T细胞淋巴瘤, with pseudoepitheliomatous epidermal hyperplasia伴假上皮瘤样增生, possibly paraneoplastic副癌综合症.

 

Medical Insight （December 15, 2007）

Self-made Audio Programme 29(本人原声)

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Welcome to Medical Insight December 15, 2007, I’m Dr. Alex Roy.

Air pollution has been associated with impaired health, including reduced lung function in adults. A study in Switzerland examined whether age-related decline in lung function was smaller in participants who had a greater decline in exposure to Particulate Matter.

Levels of PM₁₀ (particulate matter with an aerodynamic diameter <10 μm) have commonly been used to assess exposure to suspended particulate matter in the respirable range. PM₁₀ concentrations in ambient air have, on average, declined in Switzerland during the past decade. In this study, Overall exposure to individual home outdoor PM₁₀ declined over the 11-year follow-up period. There were significant negative associations between the decrease in PM₁₀ and the rate of decline in Forced Expiratory Volume in 1 second(FEV₁), FEV₁ as a percentage of Forced Vital Capacity(FVC), and Forced Expiratory Flow between 25 and 75% of the Forced Vital Capacity (FEF_25–75).

The net effect of a decline of 10 μg of PM₁₀ per cubic meter was to reduce the annual rate of decline in FEV₁ by 9%. The strongest beneficial effects of a reduction in PM₁₀ were in the small airways. Decreasing exposure to airborne particulates appears to attenuate the decline in lung function.

 

Medical Insight （December 11, 2007）

Self-made Audio Programme 28(本人原声)

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Welcome to Medical Insight December 9^th, 2007, I’m Dr. Alex Roy.

A study investigated the effects of short-term exposure to diesel traffic in people with asthma in an urban, roadside environment. Participants walked for 2 hours along a busy London street (Oxford Street) and, on a separate occasion, through a nearby Hyde Park. Participants had significantly higher exposures to fine particles (<2.5 μm), ultrafine particles, elemental carbon, and nitrogen dioxide on Oxford Street than in Hyde Park.

Walking for 2 hours on Oxford Street induced asymptomatic but consistent reductions in FEV1 up to 6.1% and forced vital capacity (FVC) (up to 5.4%) that were significantly larger than the reductions in FEV1 and FVC after exposure in Hyde Park. The effects were greater in subjects with moderate asthma than in those with mild asthma. These changes were accompanied by increases in biomarkers of neutrophilic inflammation and airway acidification. The changes were associated most consistently with exposures to ultrafine particles and elemental carbon. These observations serve as a demonstration and explanation of the epidemiologic evidence that associates the degree of traffic exposure with the severity of asthma.

In an editorial, Morton Lippmann from the New York University, School of Medicine in Tuxedo writes that both groups of researchers were able to produce statistically significant group-level effects at particulate-matter concentrations below current World Health Organization guidelines and Environmental Protection Agency standards. The magnitude of the effects was relatively small and of limited clinical relevance to individual patients, but it does have public health relevance. These studies provide additional biologic data indicating that relatively low levels of airborne particles have adverse effects on human health. Are our WHO guidelines and EPA standards too high?

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 Why does the idea of progress loom so large in the modern world? Surely progress of a particular kind is actually taking place around us and is becoming more and more manifest. Although mankind has undergone no general improvement in intelligence or morality, it has made extraordinary progress in the accumulation of knowledge. Knowledge began to increase as soon as the thoughts of one individual could be communicated to another by means of speech. With the invention of writing, a great advance was made, for knowledge could then be not only communicated but also stored. Libraries made education possible, and education in its turn added to libraries: the growth of knowledge followed a kind of compound interest law, which was greatly enhanced by the invention of printing. All this was comparatively slow until, with the coming of science, the tempo was suddenly raised. Then knowledge began to be accumulated according to a systematic plan. The trickle became a stream; the stream has now become a torrent. Moreover, as soon as new knowledge is acquired, it is now turned to practical account. What is called 'modern civilization' is not the result of a balanced development of all man's nature. but of accumulated knowledge applied to practical life. The problem now facing humanity is: What is going to be done with all this knowledge? As is so often pointed out, knowledge is a two-edged weapon which can be used equally for good or evil. It is now being used indifferently for both. Could any spectacle, for instance, be more grimly whimsical than that of gunners ourselves very seriously what will happen if this twofold use of knowledge, with its ever-increasing power, continues.

 

Medical Insight （December 9^th, 2007）

Self-made Audio Programme 27(本人原声)

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Welcome to Medical Insight December 9^th, 2007, I’m Dr. Alex Roy. Here is a case report of Peutz–Jeghers syndrome黑斑息肉综合征.A 23-year-old black woman presented to the emergency department with diffuse, colicky abdominal pain of 1 hour’s duration. The pain was followed by nausea and episodes of bilious vomiting and did not radiate or change with the patient’s position. The patient reported that a similar episode had occurred 6 months previously. At that time, she passed red blood from the rectum once but did not seek medical attention. On examination, she was restless and clutching her abdomen. Abdominal examination revealed hyperactive bowel sounds肠鸣音亢进, and a CT scan of the abdomen showed intussusception肠套叠of a segment of small intestine. On closer inspection, several small hyperpigmented lesions were detected on the patient’s fingers, tongue, and everted lips.

 

Medical Insight （December 6^th, 2007）

Self-made Audio Programme 26(本人原声)

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Welcome to Medical Insight December 5^th, 2007, I’m Dr. Alex Roy. A 47-Year-Old Man with Left Ventricular Dysfunction after Heart Transplantation---A case record from Massachusetts General Hospital.

Four weeks after he received a heart transplant, a 47-year-old man was admitted to the hospital because of ventricular dysfunction detected on echocardiography. Systemic amyloidosis with cardiomy-opathy had been diagnosed 19 months earlier; cardiac function declined rapidly, and he was admitted to this hospital to await the availability of a donor heart. The patient’s course was complicated by several episodes of cardiac arrest requiring resuscitation, and by cholecystitis.

Four months after admission, heart transplantation was performed. Although the donor’s coronary angiogram was not normal, the abnormality was thought to be of limited hemodynamic significance. The patient’s cardiac function was then normal, and biopsy specimens showed no rejection. After transplantation, he appeared to be doing well clinically, but echocardiographic examination on the 27th postoperative day showed evidence of left ventricular dysfunction. Three days later, he was admitted to the hospital with heart failure.

This case raises several issues, including the natural history and management of cardiac amyloidosis, the evaluation of donor organs before transplantation, and the differential diagnosis of cardiac failure in the early post-transplantation period.

Advanced Seconds---《新概念》个人纪录

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http://www.zshare.net/audio/54089703ebe35b/ William S. hart was, perhaps, the greatest of all Western stars, fro unlike Gary Cooper and John Wayne he appeared in nothing but Westerns. From 1914 to 1924 he was supreme and unchallenged. It was Hart who created the basic formula of the Western film, and devised the protagonist he played in every film he made, the good-had man, the accidental-noble outlaw, or the honest-but-framed cowboy, or the sheriff made suspect by vicious gossip; in short, the individual in conflict with himself and his frontier environment. Unlike most of his contemporaries in Hollywood, Hart actually knew something of the old West. He had lived in it as a child when it was already disappearing, and his hero was firmly rooted in his memories and experiences, and in both the history and the mythology of the vanished frontier. And although no period or place in American history has been more absurdly romanticized, myth and reality did join hands in at least one arena, the conflict between the individual and encroaching civilization. Men accustomed to struggling for survival against the elements and Indians were bewildered by politicians, bankers and businessmen, and unhorsed by fences, laws and alien taboos. Hart's good-bad man was always an outsider, always one of the disinherited, and if he found it necessary to shoot a sheriff or rob a bank along the way, his early audiences found it easy to understand and forgive, especially when it was Hart who, in the end, overcame the attacking Indians. Audiences in the second decade of the twentieth century found it pleasant to escape to a time when life, though hard, was relatively simple. We still do; living in a world in which undeclared aggression, war, hypocrisy, chicanery, anarchy and impending immolation are part of our daily lives, we all want a code to live by.

 

Medical Insight （December 5^th, 2007）

Self-made Audio Programme 25 (本人原声)

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Welcome to Medical Insight December 5^th, 2007, I’m Dr. Alex Roy.

The advent of Computed Tomography(CT) has revolutionized diagnostic radiology. Since the inception of CT in the 1970s, its use has increased rapidly. It is estimated that more than 62 million CT scans per year are currently obtained in the United States, including at least 4 million for children.

By its nature, CT involves larger radiation doses than the more common, conventional x-ray imaging procedures. Depending on the machine settings, the organ being studied typically receives a radiation dose in the range of 15 millisieverts (mSv) (in an adult) to 30 mSv (in a neonate) for a single CT scan, with an average of two to three CT scans per study. There is direct evidence from epidemiologic studies that the organ doses corresponding to a common CT study (two or three scans, resulting in a dose in the range of 30 to 90 mSv) result in an increased risk of cancer, especially for children. Although the individual risk estimates are small, the concern about the risks from CT is related to the rapid increase in its use---small individual risks applied to an increasingly large population may create a public health issue some years in the future.

 

Medical Insight （December 4^th, 2007）

Self-made Audio Programme 24 (本人原声)

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Welcome to Medical Insight December 4^th, 2007, I’m Dr. Alex Roy.

A 71-year-old man, whose wife died 6 months previously, presents with foot pain from diabetic neuropathy, poor sleep, lack of energy, and increasing frustration about his inability to “keep his diabetes under control.” So how should his case  and his depression be managed?

As many as 10% of adults 65 years of age or older who are seen in primary care

settings have clinically significant depression. Depression is particularly common in women, in patients with chronic medical disorders or persistent insomnia, and in patients who have experienced stressful life events, functional decline, or social isolation.

Late-life depression is often undetected or undertreated in primary care, especially in men and members of racial and ethnic minority groups. Reasons for

undertreatment include: stigma associated with depression and the belief that

depression is a normal part of aging.

Late-life depression that is untreated can last for years and is associated with a

poor quality of life, difficulty with social and physical functioning, poor adherence to treatment, worsening of chronic medical problems, and increased morbidity and mortality from suicide and other causes. Effective treatment of late-life depression has been associated with improved emotional, social, and physical functioning and quality of life. It has also been associated with better self-care for chronic medical conditions and reduced mortality.

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 How it came about that snakes manufactured poison is a mystery. Over the periods their saliva, a mild, digestive juice like our own, was converted into a poison that defies analysis even today. It was not forced upon them by the survival competition; they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do. Poison to a snake is merely a luxury; it enables it to get its food with very little effort, no more effort than one bite. And why only snakes? Cats, for instance, would be greatly helped; no running fights with large, fierce rats or tussles with grown rabbits -- just a bite and no more effort needed. In fact, it would be an assistance to all carnivores though it would be a two-edged weapon when they fought each other. But, of the vertebrates, unpredictable Nature selected only snakes (and one lizard). One wonders saliva into why Nature, with respect from that of others, as other on the blood.
In the conversion of saliva into poison, one might suppose that a fixed process took place. It did not; some snakes manufacture a poison different in every respect from that of others, as different as arsenic is from strychnine, and having different effects. One poison acts on the nerves, the other on the blood.
The makers of the nerve poison include the mambas and the cobras and their venom is called neurotoxic. Vipers (adders) and rattlesnakes manufacture the blood poison, which is known as haemolytic. Both poisons are unpleasant, but by far the more unpleasant is the blood poison. It is said that the nerve poison is the more primitive of the two, that the blood poison is, so to speak, a newer product from an improved formula. Be that as it may, the nerve poison does its business with man far more quickly than the blood poison. This, however, means nothing. Snakes did not acquire their poison for use against man but for use against prey such as rats and mice, and the effects on these of viperine poison is almost immediate.

Advanced Seconds---《新概念》个人纪录

 

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