Abstract: An apparatus useful for studying cells in culture under conditions which reproduce their natural, in vivo mechanical environment is disclosed. The device comprises an airtight well having an optically transparent compliant base of a biologically compatible material on which said cells may be grown and an optically transparent, removable cap, coupled with a ported, airtight reservoir which reservoir has an optically transparent base and which reservoir can be filled with pressurizing media to create cyclic variations in hydrostatic pressure beneath said compliant base, causing said compliant base to deform and thereby exert a substantially uniform biaxial strain on the cells attached thereto.

Abstract: A system for obtaining a hemoglobin-oxygen equilibrium curve for a sample of concentrated hemoglobin solution or whole blood. Gaseous oxygen and/or nitrogen is used to oxygenate or deoxygenate the sample. The exchange takes place across a gas-receiving cup-shaped semipermeable membrane in a temperature-controlled chamber containing the sample, in an annular space defined between the cup-shaped gas-receiving membrane and the chamber wall. The rate of oxygen transport into and out of the sample is continuously calculated by means of a microcomputer. Simultaneously the solution pO.sub.2 is measured by means of a Clark electrode exposed to the sample. From the oxygen transport rate calculation and the pO.sub.2 measurement, the percent O.sub.2 saturation is calculated and is plotted against the change in pO.sub.2. Oxygen can be exchanged bidirectionally with the sample across the semipermeable membrane, which is positioned concentrically in a cylindrical sample cavity.