Regulation and actions of gastrointestinal somatostatin.
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Biomedical subjects
G L Pittenger
Publications and source records attributed to G L Pittenger.
Adequacy of tissue oxygenation in intact dog intestine.
Changes in O2 consumption, O2 extraction, and intramural pH, resulting from a decreasing O2 delivery, were studied in the intact dog intestine. The O2 delivery was decreased by ischemia, hypoxia, and combined hypoxia-ischemia. A noninvasive approach for determining intramural pH based on the principle of tonometry was used. There was a strong correlation between the changes in intramural pH and intestinal O2 consumption as O2 delivery was decreased. Intramural pH and O2 consumption were initially maintained in the face of decreasing O2 delivery, but after a critical point they decreased. This critical point was 60.3 +/- 1.6% of base-line O2 delivery in the ischemic group and 51.3 +/- 2.7% of base line in the hypoxic-ischemic group. Despite a decrease to 36.0 +/- 5.6% of base-line O2 delivery, the intramural pH and O2 consumption did not decrease in the hypoxic group. O2 extraction increased with decreasing O2 delivery but did not plateau, indicating no diffusion limitation. The data suggest that blood flow is the major factor limiting intestinal O2 consumption. It is concluded that the noninvasive measure of intramural pH is a good marker of the adequacy of tissue oxygenation in canine intestine.
Animals↗
Blood loss measured with indium-111-labeled red blood cells in dogs.
The authors describe a safe, simple, sensitive, and accurate technique of measuring moderate amounts of blood loss using erythrocytes labeled with indium-111. Donor red cells were labeled with indium-111 and tracer amounts infused into dogs. The magnitude of red cell loss was determined by the difference between two sequential volume measurements. The coefficient of variation of sequential measurements of the same red cell volume was 4.6 +/- 1%. The sensitivity of the technique, as determined by comparison of measured and estimated volumes, was 20.5 ml. The measured volume was related linearly to the calculated volume of red cells lost (r = 0.98). The authors recommend indium-111-labeled erythrocytes as a means of obtaining multiple measurements of small to moderate amounts of hemorrhage.
Animals↗