Analysis of breath-by-breath exercise data from field studies.

We describe a system useful for collecting and analyzing breath-by-breath exercise test data in the field. In studies of untrained subjects, analysis of artifacts is particularly important. Our system uses pattern-recognition criteria to reject breaths if the breathing valves do not operate satisfactorily or if deviations from the calibrating baseline occur.

Effects of hemodilution on O2 transport in high-altitude polycythemia.

A native of the Peruvian Andes (4,250 m) was studied before and after isovolemic hemodilution of the hematocrit from 62 to 42%. O2 transport was studied with newly developed catheters in the radial and pulmonary arteries. These catheters allowed continuous measurement of arteriovenous O2 content and intermittent cardiac output by thermodilution.

Development of a reference material for alkaline phosphatase.

In developing a Reference Material for alkaline phosphatase, we studied the stability, kinetic properties, and commutability of separate preparations of the purified enzyme from human liver, intestine, bone, and placenta. The Michaelis constants (Km) for the preparations from liver, bone, and intestine agreed well with the Km values we obtained for five human serum specimens, whereas that for the placental isoenzyme differed significantly. The first three isoenzymes exhibited nearly identical response-surface patterns, which closely paralleled those observed for 12 human serum specimens (commutability), but not that of the placental isoenzyme.

The development and evaluation of a homogeneous immunoassay for the isoenzymes of aspartate aminotransferase.

Purified isoenzymes of aspartate aminotransferase (AST) from human liver (mitochondrial) and erythrocytes (cytoplasmic) were used to elicit antisera in rabbits. Each antiserum was characterized for titer and specificity. Complexes formed upon addition of each isoenzyme to its specific antiserum were demonstrated to be catalytically inactive.

Stability of creatine kinase-3 in lyophilized materials.

We examined the stability of creatine kinase (EC 2.7.3.