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We describe the design, the development, and the calibration of a radiometer to measure water vapor abundance in the middle atmosphere, using the solar occultation technique from an orbiting platform. The use of gas cells containing water vapor and carbon dioxide leads to a relatively simple, but sensitive, design. This radiometer is shown to be capable of detecting water vapor in the mesosphere, where, because of dissociation by the Sun, the amounts are very small, of the order of 1 part per 10(6) or less. A flight version of the instrument will be launched in 1992 on board the European Retrievable Carrier space platform, and the data will be employed for a better understanding of the Earth's water budget.

Bacterial endocarditis secondary to endoscopic procedures has been convincingly documented in only four cases. We describe a case of prosthetic valve endocarditis due to Cardiobacterium hominis that developed after upper gastrointestinal endoscopy. Because of this, we recommend subacute bacterial endocarditis prophylaxis in patients who have a prior history of endocarditis or valve replacement.