Do you think it ethical and appropriate for Marshall to have used himself as a test subject and swallowed a sample of Helicobacter pylori? What precautions did he take? Would you do it? Why or why not?
2. How did the colloidal bismuth subcitrate (CBS) experiment provide evidence supporting Warren and Marshall’s hypothesis? 3. Answer the following questions based on the data presented in Fig.
3: a. In Table II, of those patients with ulcers, how many were positive for H. pylori? Of those patients with normal endoscopic results, how many were positive for the bacteria? b. Based on this data, Warren and Marshall hypothesized that there was a causal relationship between ulcers and bacterial infection. But there were 4 patients with ulcers that were negative for the bacteria. Why is this not signif cant? c. If there is a causal relationship between the presence of H. pylori and ulcers, how might you explain that 50% of the patients with a normal endoscopic examination were infected with the bacteria? d. In your own words, explain the results presented in Table III. What do you conclude from this data?
4. Robert Koch was a German physician who identifed the bacteria causing anthrax and tuberculosis. His methods established four criteria that must be met for a specifc pathogen to be considered the cause of a disease. T ese four criteria are listed below. For each one, discuss whether Warren and Marshall fulflled them and, if so, how. I. Te pathogen should be found in the bodies of animals having the disease. II. Te suspected pathogen should be obtained from the diseased animal and grown outside the body.
“Helicobacter pylori and the Bacterial Teory of Ulcers” by Debra Ann Meuler Page 6
III. Te inoculation of that pathogen, grown in pure cultures, should produce the disease in an experimental animal. IV. Te same pathogen should be isolated from the experimental animal after the disease develops.
5. What role did chance, assumptions, and curiosity play in Warren and Marshall’s research on Helicobacter pylori?
6. Describe how the story of Warren and Marshall’s discovery illustrates the process of science.
7. How does this case illustrate the tentative nature of science? 8. How does this case illustrate the role of technology in scientif c progress?
9. Why is this discovery significant? Do you think it is worthy of a Nobel Prize?
10. What does the Helicobacter story tell us? What lessons can be learned from this story?
11. Albert Gyorgyi, 1937 Nobel Laureate in Physiology and Medicine, once said in his Nobel award speech: “Discovery consists of seeing what everybody has seen and thinking what nobody has thought.” Describe how this statement applies to Warren and Marshall’s pioneering work on peptic ulcer disease.
