- 18 to 60 years of age adult volunteers, mentally competent, willing and able to give written informed consent prior to study entry, suffering from at least one of these chronic diseases:moderate to severe hypertension, moderate to severe congestive heart failure, chronic obstructive pulmonary disease (COPD) or moderate to severe asthma, moderate to severe hepatic or renal insufficiency, arteriosclerotic disease or insulin dependent diabetes mellitus