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发表于 2010-7-7 21:02 |只看该作者 |倒序浏览 |打印

How Medical Safeguards Evolved
Ways to protect patients have been developed over a period of several decades in response to circumstances in which the rights of patients were not respected and patients were harmed.  M7 A2 ]( ?; Y0 [* K: i
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An early attempt to establish formal international guidelines, found in a document called the Nuremberg Code, came shortly after World War II. The Nuremburg Code (1947) was formed in direct response to experiments conducted in Germany on prisoners during the war. This code includes statements that research must have the voluntary informed consent of the persons being experimented on and an indication that the treatment was unlikely to be harmful.
The Tuskegee Syphilis Study led to the adoption of Institutional Review Boards (IRBs) in the United States, legally enforcing an independent review of studies using human subjects. The Tuskegee Syphilis Study followed the progression of syphilis in nearly 400 African-American men over a period of 40 years without informing them that there was an effective treatment. As a result many died from the disease, and their wives and children became infected as well. This study led to the creation of ethical guidelines known as the Belmont Report (1979), which calls for three principles to be followed in human experimentation: respect for persons, beneficence (promoting the well being of others) and justice.
Another cornerstone of ethical human experimentation is the Helsinki Declaration, first published in 1964, and subsequently revised several times, most recently in 2008. These guidelines call for the approval of a research ethics committee, scientific evidence suggesting the experimental treatment can be expected to be beneficial, as well as many other principles.
What Can Happen When Safeguards are Not Followed or Put in Place/ ]8 r5 o; D; m6 d9 |. X
Boy Develops Brain Tumor as a Result of Stem Cell Therapy  \; P9 c( Y6 Y$ l$ v5 X6 R
In February 2009, the journal PloS Medicine published an article detailing a case study of a 13-year-old boy who had developed a brain tumor as a result of a stem cell treatment. The boy had a genetic condition called ataxia telangiectasia, a neurodegenerative disease that causes, among other symptoms, poor movement coordination.

Between 2001 and 2004 the boy received three separate fetal stem cell transplants at an unnamed treatment facility in Russia. In 2005 he developed headaches, and was found to have a brain tumor. The tumor was found not to have originated from the boys own cells, but rather from the fetal stem cells. The evidence for this was that none of the tumor cells carried the genetic mutation that causes ataxia telangiectasia, which would have been found in all his cells. In addition, the tumor cells were a mix of male and female, indicating the tumor actually originated from two separate donors. The tumor was removed surgically, and at the time the article was published, the boy was in stable condition and the remaining tumor tissue was not significantly growing. At the time he developed the brain tumor, the boy still had typical symptoms of ataxia telangiectasia.
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The New Zealand Cervical Cancer Study
In the 1950s and 60s it was already generally accepted that cervical cancer could be prevented by treating women who were found to have precancerous cells called Carcinoma In Situ (CIS). The methods at the time to treat women with CIS usually involved either a hysterectomy, the surgical removal of the uterus, or a cone biopsy which could cause bleeding and fertility problems. Professor Herbert Green, a doctor in Auckland, New Zealand, hypothesized that CIS was not a precursor to cervical cancer, which was contrary to scientific consensus, and embarked on a study to prove his theory and show that women could be spared the negative effects of treatment. He primarily elected to leave untreated identified cases of CIS in young women (under 35), as his main objective was to preserve fertility. The women were never informed they were in a study, never told they had treatment options, and in some cases never were told they had CIS.4 b2 r5 F% A5 e5 u

The study ran from 1955-1976, although it officially began in 1966 when the hospital approved the study. During that time 131 women tested positive for CIS, of which 22% developed invasive cancer and some died as a result. Only 1.5% of women with normal pap smears developed cervical cancer.* y$ \0 ?( P& ?& n8 p
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The study continued despite evidence that the doctor's theory that CIS did not lead to cancer was wrong. Several regulatory guidelines outlined in both the Nuremberg Code and Helsinki Declaration were ignored. Patients were not properly informed, there was no effort to minimize harm to the patients, and scientific evidence, both indicating that CIS did lead to cancer and that the lack of treatment was harmful, was ignored.8 @6 \9 Z& u) y* K  J  J
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Thalidomide
In 1957 the German company Chemie Gruenenthal developed and marketed the drug thalidomide as a sedative. Barbiturates, the sedatives available at that time, have a low safety margin and improper use can easily result in a fatal overdose. At the time there was a great demand to find safer sedatives. In animal testing of thalidomide, researchers were unable to find a dose high enough to kill animals. It was therefore thought that thalidomide would not cause fatal overdoses in humans, and it was deemed safe. The drug was rushed into market in countries throughout Europe, and in Australia, and Canada. In many countries the drug was considered so safe it was sold over the counter, and in some it was also given to pregnant women as a remedy for morning sickness.
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Chemie Gruenenthal, however, neglected to perform a well-designed, controlled clinical trial before widespread distribution as a sedative, and despite differences in how humans and animals react to thalidomide, relied primarily on the animal tests to indicate safety. It was found in time that thalidomide was far from safe. Around 1960 doctors began noticing that some patients who had used thalidomide developed polyneuritis, numbness in the hands and feet, caused by permanent nerve damage. At around the same time, physicians began noticing a dramatic increase in the normally rare birth defect phocomelia, in which the legs and/or arms are severely malformed or missing. Many such children were also born with severe defects to the bowel that often proved fatal.

The sudden increase in a rare birth defect was found to be directly linked to thalidomide use. It was found that a single dose of this "safe" drug during a critical period in pregnancy was enough to cause birth defects. Following the revelation of these severe side effects, thalidomide was taken off the world market through 1961 and 1962. During the time the drug was available it caused approximately 40,000 cases of nerve damage. More than 10,000 children were born with thalidomide-induced deformities, and, of these, approximately 40% died.: Q+ D& H3 H  B, {- y6 L: u7 z7 P2 }
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Thalidomide was never marketed in the United States because the U.S. Food and Drug Administration (FDA) deemed there was not enough evidence indicating the drug was in fact safe. Except for a few experimental test cases, the United States was largely spared.$ K6 m$ {9 d1 p* Z! s7 W7 f
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Elixir Sulfanilamide
Sulfanilamide was one of the first antibiotics developed and was found to have dramatic curative effects for streptococcus infections. It was available in the United States beginning in the early 1930s in powder or tablet form. One major drawback of the drug was a very bitter flavor. The drug company S. E. Massengill attempted to form a more palatable drug and found that sulfanilamide could dissolve in diethylene glycol. The mixture was found to have a sweet, raspberry flavor, and in September of 1937 it was marketed to public as Elixir Sulfanilamide. No testing on either animals or human subjects occurred prior to distribution.

The company failed to detect that diethylene glycol, a chemical sometimes used in anti-freeze, is extremely toxic and causes kidney failure, vomiting, abdominal pain, convulsions and eventually death. Individuals could survive up to three weeks after ingestion. In October, about one month after the elixir was distributed, the American Medical Association and the U.S. Food and Drug Administration (FDA) pushed to recall the drug and return shipments, but not before more than 100 people died as a result of taking the medication.3 w# t, q4 {/ }4 Q: K+ ?

This page was last updated June 7, 2010