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Elderly adults are at greatest risk of stroke and myocardial infarction and have the most to gain from prophylaxis. Patients ages 60 to 80 years with blood pressures above 160/90 mm Hg should benefit from antihypertensive treatment.
Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
Sildenafil (Viagra®) has two actions that may be of consequence in patients with heart disease. It can lower the blood pressure, and it can interact with nitrates. It should never be used in patients who are taking nitrates.
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.
Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.