reader (the Second)
Rancher
Joined: 10 Feb 2005
Posts: 4870
Location: Northern Virginia
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 Posted: Thu Aug 25, 2005 9:54 pm Post subject: For Kathy |
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The man I'm dating told me about how a novice came up with a theory about what causes ulcers and how his theory was rejected by all the experts. I thought of you 
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7. Early Reception of the Bacterial Theory of Ulcers
Barry Marshall (1989, p. 19) was convinced that the new bacterium was the primary cause of peptic ulcer disease by 1983, after an experiment involving 100 patients tested for presence of the bacterium and presence of stomach disease. All 13 patients with duodenal ulcer had the bacterium, and the association between gastric ulcers and the bacterium was also statistically significant (Marshall and Warren, 1984). Marshall was relatively new to gastroenterology, having only begun specialized training in the field in 1981. Accordingly, his adoption of the new hypotheses did not require abandonment of a set of well entrenched beliefs that conflicted with the new ideas. In contrast, other more established medical researchers and practitioners had beliefs about the nature and treatment of ulcers that clashed with the new hypotheses and led them to reject them summarily.
Hypothesis 1, that members of a previously unidentified species of bacteria inhabit the human stomach, was initially greeted with incredulity because of prevailing beliefs about the stomach. According to Blaser (1989, p. 1), "most physicians believed that the normal human stomach, because of its high acid concentration, was sterile except for transient bacterial flora." Hypothesis 1, however, was quickly established as numerous researchers who had specialized in research on Campylobacter infections in humans turned their attention to what was taken to be a new species of that genus. The new bacteria could be microscopically observed using the staining techniques introduced by Warren, and they could be grown in the laboratory using the culturing techniques developed by Marshall. The apparent conflict between the acidic nature of the stomach and the existence there of bacteria has been resolved by discoveries about the nature of H. pylori. These bacteria are able to burrow beneath the mucous layer in the stomach, and they produce an enzyme, urease, that uses urea present in the gastric juice to generate ammonia, an alkaline that neutralizes acid (Marshall, et al., 1990). Bacteriologists were therefore quick to accept the hypothesis that a newly recognized kind of bacteria inhabit the human stomach.
Many gastroenterologists, however, found it much more difficult to consider a challenge to accepted views about the causes of peptic ulcers. By the early 1980s, it was widely believed that excess stomach acid is the main cause of peptic ulcers. People with increased amounts of acid were found to me more likely to get the disease, and cimetidine (brand name Tagamet) and ranitidine (brand name Zantac) were found to be effective antacid means of healing ulcers. Physicians thus had both an explanation in terms of excess acidity of why some people get ulcers, and an effective means of treating those people with Tagamet and Zantac, which remain among the most widely prescribed drugs. Hence hypothesis 2 that ulcers are caused by bacteria clashed with the hypothesis that acidity is the main culprit in peptic ulceration, and hypothesis 3 clashed with the effective standard treatment. It is not surprising, therefore, that many gastroenterologists rejected the new hypotheses as incoherent with what was already known (see section 4). Hence Marshall, a young, unknown Australian who put forward his new hypotheses with confidence amounting to brashness, was viewed as crazy.
In retrospect, however, there were problems with the accepted view of ulcers. It was not known why some people have excess acidity, although conjectures were made about genetic factors and psychological factors such as stress. The popular view of ulcers as a psychosomatic, stress-induced disease had given way to the emphasis on excess acidity, but stress remained one possible indirect explanation of ulcers, since it was known that stomach acid secretion increases in animals under stress. Even more important, although antacid drugs were usually effective in controlling the symptoms of ulcers, it was well known that recurrence of ulcers was common: the drugs clearly did not produce a cure. Hence when Marshall began to develop alternative hypotheses about the causes and treatment of ulcers, some researchers took them seriously enough to test them. Marshall, Warren, and their collaborators undertook to accumulate evidence concerning the cause and treatment of ulcers. |
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