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Biomedical subjects

A Davies

Publications and source records attributed to A Davies.

At least 307 records · Page 17Linked to original sources
PubMed1977

Fibrin and fibrinogen proteolysis products: comparison between gel filtration and SDS polyacrylamide electrophoresis analysis.

The proteolysis of purified human fibrinogen, stabilized and non-stabilized fibrin by plasmin were investigated by gel filtration analysis and SDS polyacrylamide electrophoresis of the reaction products. Plasmin proteolysis of fibrinogen followed the sequential steps previously reported and the two analytical methods yielded concordant results. Large molecular weight proteolysis products, of substantially greater molecular weight than native fibrinogen, were identified by gel filtration analysis following dissolution of stabilized and non-stabilized fibrin clots; with further incubation with plasmin, these proteolysis products gradually diminished in size. On the other hand, SDS polyacrylamide electrophoresis of these fibrin digests demonstrated that while non-stabilized fibrin yielded breakdown products similar in size to those obtained after proteolysis of fibrinogen, stabilized fibrin digests showed moieties of greater molecular size estimated to be of molecular weight 400,000 to 800,000. The final breakdown products of stabilized fibrin differed from those of fibrinogen and nonstabilized fibrin in that fragment D was present in the "double D" cross-linked form.

Antigens↗
PubMed1977

Role of conducting airways in partial separation of inhaled gas mixtures.

A positive (hollow) cast of the bronchial tree was made from a pig's lung. Gas mixtures containing sulfur hexafluoride (SF6) and helium (He), and SF6 and argon (Ar), were blown down the cast at two different flows, the cast having first been filled with air. Gas was sampled by a mass spectrometer probe from 1-mm-diam branches situated on short, medium, and long pathways. The front of the SF6 appeared in advance of the fronts of the He and the Ar. This relative advancement was greater a) with the SF6/He mixture than with the SF6/Ar mixture; b) at slower flows; and c) on longer pathways. With reverse flow up the cast using SF6/He there was little differences between the arrival times of the two gas fronts at either flow. These results could be explained by the effects of Taylor dispersion on gases having different diffusion coefficients.

Animals↗
PubMed1975

Gas transit times in the pig lung.

1. A method of measuring the time taken by a front of gas to pass from the carina to individual small airways in the lung is described. 2. This method has been used to investigate the movement of a gas front through hollow lung casts, excised lungs, and excised lungs subjected to a gradient of pleural pressure. 3. The results obtained support the suggestion of morphometric studies that the asymmetrical anatomy of the bronchial tree plays a part in the uneven distribution of ventilation in the lung. 4. The effect of a gradient of pleural pressure over the surface of the upright lung was to increase the time taken by a gas front to reach dependent regions.

Animals↗